Natural History Review/Series 2/Volume 1/Number 3/Anatomical Notes

by Josef Hyrtl

XXXII.—Anatomical Notes.—By Professor Hyrtl of the University of Vienna.

[Professor Hyrtl has kindly promised to favour me, from time to time, with the communication of a series of his Anatomical Notes; some of which will be found in the future proceedings or transactions of the K. K. Akademie der Wissenchaften, Wien. But as these are not published at any fixed periods, it will very generally happen that the epitome of such papers given in these pages, will have some months priority over the more detailed descriptions given in the Publications of the Academy. Some few, perhaps, will be familiar to those learned in German Bibliography, but will probably still be new to most readers; others, again, will be printed here for the first time. It is but justice to Professor Hyrtl, well known to be an excellent English scholar, that I should hold myself responsible for the English of these notes, and I trust that the sense, at least, of what my friend would say, will always be given, even though I may not have succeeded in translating into very terse or elegant language, some of the more complex of the compound German words.—E. P. W.]

 

1.—On Anangious Retinas.

In the xxxiii. volume of the "Sitzungsberiehte der naturwiss. Classe der kais. Akademie der Wissenchaften zu Wien," I published a treatise on hearts devoid of nutritive blood-vessels. (Ueber gefässlose Herzen). I there demonstrated, by microscopical investigations, that the heart, in all the Amphibia, presents the remarkable peculiarity, that the Arteria coronaria, which arises from one^[1] of the first branches, into which the Bulbus arteriosus splits, and at some distance from the heart, supplies only the Bulbus arteriosus itself; and that not the smallest arterial branch enriches the muscular substance of the Ventriculus, or of the Atrium cordis.

I have likewise demonstrated, that the heart of Sauria, Ophidia, and Chelonia, is also partially deprived of blood-vessels; in them, the outermost layer of the muscular stratum of the heart, possesses, like all the other muscles, a capillary network, but still, the greater part of the heart-mass is entirely destitute of nutritive blood-vessels. This is the case, too, with all the osseous Fishes, while the more highly organised Rays and Sharks have, like warm-blooded animals, the coronary arteries distributed to the whole muscular coat of their hearts. In the paper, alluded to, I have stated the reason why such an apparent anomaly is, in these several cases, quite in accordance with physiological principles; and I need not further allude to the matter here. My reason for referring to it at all is that I have now met with the same exclusion of all nutritive arteries, in a different organ, and not only is the organ one of similar importance, but it also presents so constantly this state of anangia (a priv.—αγγεῖον), that the latter becomes almost an anatomical characteristic of certain classes of Vertebrata.

The retina of all Birds, Reptiles, Amphibia and Fish, osseous and cartilaginous, contains not the slightest trace of blood-vessels, so that the vascularity of the retina occurs only in the Mammalia. I communicated a short notice of this interesting anatomical fact to the Academy of Sciences in February, which will not, however, be printed until towards the end of the year (1861), as there are many prior papers for publication. Hence, I have thought, that a note of the existence of these anangious retinas would not be without interest for the readers of the Natural History Review. I trust, that those engaged in optical inquiries, will see the importance of this discovery, for the assertion of physicists, that the blood-vessels of the retina must absorb some of the rays of light, and so cause certain imperfections in the vision of minute objects, cannot hold as true for all eyes, now that the existence of bloodless retinas is an established fact.

The retina then, of four classes of vertebrate animals is not nourished by the direct intervention of the circulatory system, and can be preserved in health and vigour, only by some endosmotic process.

And here I may mention, that this endosmotic action is limited in birds to the choroid surface alone. In the other three classes, Reptiles, Amphibia and Fish, absorption, on the contrary, may take place both from it and from the hyaloid membrane. This latter membrane, as I was the first to show, many years ago,^[2] is in some reptilia and amphibia a highly vascular one, and late investigations of mine have made it evident, that the hyaloidea of all fishes perfectly resembles that of the reptiles alluded to, in the richness of its supply of blood-vessels. The result of these investigations I reserve for a special treatise on the vascularity of the hyaloidea of fish. This subject is one well worth further investigation.

 

2. On some peculiarities of the gills of Lutodeira Chanos Forsk.

I have had an opportunity of investigating the anatomy of this very rare and most valuable fish, and have discovered the following modifications to exist in its respiratory apparatus, which though partially found in some other clupeid and salmonoid fish, yet are most fully developed only in this genus.

Attached to the gills there is an accessory respiratory organ, presenting the form of a tube, partly membranous, partly cartilaginous; this tube is twisted upon itself like a helix, one and a half-times, and is of equal calibre throughout: its length is one inch and three quarters and its diameter is two lines. It is situated above the fourth branchial arch, whose epibranchial segment (Owen) is expanded into a broad triangular plate; the accessory organ lies upon this plate in such a manner, that the axis of its spiral canal keeps a perpendicular direction throughout.

The right and left organs communicate by a common aperture with the roof of the pharynx, immediately behind the toothed pharyngo-branchial segments (Owen, pharyngiens superieurs Cuv.) The lining membrane of these organs is very vascular, and fine injection proved beyond contradiction, that their arteries are but prolongations of those which bring the venous blood to the gills. Their veins unite with the root of the aorta, and must, therefore, contain arterialised blood. On the inner border of the twisted tube there is a double row of fringes, of the consistency of cartilage, and a groove lies between the two rows, but there is no interspace^[4] like a branchial cleft.

Our great anatomist Johannes Müller, threw out a hint of the existence of this organ in his admirable work "Bau und Grenzen der Ganoiden," p. 74 et seq.; but the specimen which he had for dissection was probably so defective as to cause him entirely to overlook its peculiar snail-like convolution, and he only speaks of the above mentioned double series of fringes, which he declared to be a true biserial gill. Careful investigation of well injected preparations, has, however, satisfactorily convinced me, that the biserial gill of Müller is not a respiratory gill, but simply a continuation of the peculiar horny fringes, which are attached to the concave border of the branchial arches in many Clupeid and Scomberoid fish, and which serve as combs, or gratings, to intercept any solid particle swallowed, which if forced through the interspaces of the branchial arches would, most certainly, injure the very delicate vascular net-work, supported by the slender and compressed processes of the gill fringes.

A very large branch of the pneumogastric nerve supplies the inner side of this organ (to which I give the name of Cochlea branchialis), and it strikes me that its mucous membrane may be capable of receiving some special sensation. The organ is surrounded by a strongly developed muscular coat, so that the water contained in it can, by the contraction of the muscles, be easily expelled through the same orifice by which, on dilatation, it enters.

On a former occasion^[5] I have pointed out that some of the true clupeid fish, as Meletta, Chatoessus, Chipanodon, Gonostoma, &c are also provided with a cochlea branchialis, to which, the organ described in Lutodeira, is, in its form, structure and uses, quite similar.

I may add that a few genera of the Salmones (Cuv.) or rather Characini (Müll.) viz. Prochilodus and Citharinus, also possess an accessory respiratory organ, well supplied with nerves from the Vagus; it is situated above their gill chambers, and is either a straight blind chamber, or has a curved sac-like form, in both cases receiving venous blood from the heart, and returning red blood to the base of the aorta. My friend, Professor Kner, a short time since, showed me the same organ in Anodus.

The following peculiarities in the structure of the gills of Lutodeira are unique, no other clupeoid or characine fish affording a trace of them:—

1st. Each interspace between the branchial arches is divided into a superior and inferior compartment by a short, strong and non-elastic ligament, which unites the articulations of the basi- and cerato-branchial bones (Owen) of each arch, with the like articulations of the same bones, opposite to them. The branchial arches therefore cannot be divaricated from one another, and their interspaces, the branchial clefts, cannot be so much dilated as in other fish, but they remain permanently in a state of extreme narrowness, and the current of water which passes through them, must necessarily be very small.

2nd. The cartilaginous combs, or fringes, attached to the concave borders of the branchial arches, are set in two rows on each arch; these two rows are likewise divergent, so that the tips of the fringes of the outside row of one arch, meet the tips of the fringes of the inside row of the next one. The tips of each pair of fringes firmly coalesce and cannot be separated without breaking them. Each branchial cleft is therefore bridged over by a succession of gothic arches, equal in number to the cartilaginous filaments in every fringe, and there is no free passage for the current of water. The water is, therefore, it may be said, filtered through the coalesced fringes, whose tips are directed towards the mouth, and, whatever may be the amount of heterogenous particles in the water, they must be with certainty caught between the pallisades, just as a fish is caught in a net; the surprising length, fineness and delicacy of the respiratory branchial lamellæ on the convex edges of the branchial arches, and the excessive richness of their capillary net-work of vessels, are such as fully to account for all these elaborate guards against mechanical injury to so frail an organism.

 

3. On a peculiar arrangement of the Gill chamber in Poly acanthus.

This fish, one of the Labyrmthidæ, presents a very peculiar arrangement of its gill chambers.

The first five vertebræ are each furnished with four ribs instead of two; this is quite a unique arrangement in the osteology of fishes. These supernumerary ribs are attached to the sides of the neural-spine (Owen) far above the neural arch. They are somewhat shorter than the true ribs, which are articulated to the bodies of the vertebræ. But they are so curved, that the inferior end of each reaches to its corresponding true rib, and articulates with the latter near its head. The first supernumerary rib is the longest, and the others gradually decrease until the last, which is the shortest.

A dense fibrous membrane lines the spaces which intervene between these ribs, so that there exists, on each side of the dorsal spine, and covered over by the superior muscles of the vertebral column, a long conical cavity, whose apex is directed upwards and backwards, and whose base opens downwards into the branchial cavity. In this cavity is lodged a good deal of the branchial labyrinth of the fish.

The labyrinth of Polyacanthus is not of the complicated nature of that of Anabas, Helossoma, or Osphromenus, but, in the simplicity of its structure, more resembles that of Ophiocephalus; it is composed of but three heliciform lamellæ, which, however, make up in length, what they want in the sub-division of their lamelliform surfaces, and are so long that they cannot be sufficiently protected by the upper portions of the tympano-maxillary and humero-scapular arches.

An organ like the labyrinth of this fish, with such important functions to perforin, could not well be lodged in the trunk, where it would be in the way of powerfully acting muscles, but it is quite securely situated, under the rib-like protection of this kind of thorax, formed by the five pairs of accessory ribs.

No other known Labyrinthoid fish (I have them all in abundance) presents a similar anomaly.

 

4. Some results of isolated Arterial Injections.

Isolated arterial injections are in many respects very instructive; by "isolated injection" I mean the injection of the minute arteries, not of those supplying an extremity, or other large portion of the body; these latter will never give the same clear idea of the province which belongs to each small arterial branch, whilst the isolated injection of the minute arteries shows the boundaries of the territories, which are irrigated by certain sets of blood-vessels. When an organ receives several arteries, then the isolated injection of each with differently coloured injections, will show, in a most satisfactory manner, what portion of the organ is supplied by each branch. So far as the nervous system is concerned, anatomists have marked out the districts over which the ultimate nervous ramifications spread; the same might be done for the arterial system by means of these isolated injections, and most beautiful and instructive preparations can be obtained by injecting, with differently coloured materials, the arteries of the conjunctiva, the mucous membrane of the nostrils, or the lining membrane of the mouth, pharynx, urinary bladder, &c.

The following results of a long series of such injections may merit attention, as some of them are of high practical importance.

 

Coronary Arteries.

When a single coronary artery of the heart is injected, the other (say the right) remains empty, showing that there is no anastomosis between the primary, or secondary, ramifications of these two arteries, in the circular and longitudinal grooves of the surface of the heart, as all anatomists say they have observed. When the injection passes from one artery to the other, it is always through the intervention of the capillary system that the communication takes place; never through the non-capillary system; hence it follows, that the right and left hearts are, to this extent, independent as far as regards their arterial circulation.

 

Arteria lingualis.

The same is likewise the case with the right and left lingual arteries. When the right lingual artery is injected with colouring matter, only one-half of the tongue becomes coloured, the other half remaining as it is. If the assumed anastomosis really existed between the two arteries (forming an arch in the top of the tongue) the injection of the one artery would certainly fill that of the opposite side.

 

Arteria laryngea superior.

When the Arteria laryngea superior is separately injected, it is necessary to put a ligature on the Art. thyreoidea inferior of the same side, because there is a very extensive anastomosis between the former and the laryngeal branch of the latter; this anastomosis will be found in the interior of the larynx (between the thyroid and cricoid cartilages); perhaps this fact admits of, the following interpretation: The superior laryngeal artery is not exposed to muscular compression, but the inferior thyroid, which gives a branch to the larynx, may occasionally be compressed by vehement contraction of the muscles under which it wends its way. The intra-laryugeal anastomosis of both is so arranged, that the necessary supply of blood cannot be stopped by such compression.

 

Uterine Arteries, &c.

In the uteri of children, of which I have several well injected preparations, the right and left arteries appear to he as independent as those of the heart. An injection of the arteries of one side is always followed by the perfect filling of the vessels of that side, and the absence of injection in the other. However, in the vagina, and more especially in the bladder, there are large anastomoses between the right and left arteries of these organs, a circumstance which is of some importance in the development of certain pathological changes. When, in man, there are two, three, four, or even (as sometimes) five renal arteries, you may inject one, and yet none of the others will be filled, every one of these arteries having a distinct province of its own. It is the same case in other Mammalia, when their kidneys have more than one artery entering at different portions of their surface; for instance, when an injection of the horse's kidney is made, one can spare the injected matter, by selecting any small artery which enters the external surface of the organ (not in the hilus). A minute injection of a very limited portion of the cortex is thus obtained, and there is no risk of wasting the injected material by filling other parts, not required for the preparation.

Meningea media.

An isolated injection of the middle meningeal artery makes it evident, that this artery is not only destined to be the nutritive artery of the cranium, but also, that very numerous off-sets of the diplöetic branches pass out to the external surface of the calvarium and ramify freely throughout the pericranium. When a well injected preparation of this artery is exposed to the action of weak hydrochloric acid, the destruction of the earthy matter gives to the skull (after being well dried and saturated with turpentine) such a degree of transparency, that the perforating branches of the diplöetic arteries can be distinguished with the greatest facility.

 

Arteria occipitalis.

It happens very often, that the occipital artery seems to send a branch through the mastoid foramen; it is very commonly believed that this branch appertains to the dura mater, and is an accessory nutritive artery (Art. meningea externa accessoria). Now, when a series of isolated injections of the occipital artery are made, it is easy to show that, in many instances, the artery which passes into the mastoid foramen does not pass through it, and that it is, therefore, no meningeal artery. The hammer and chisel, or the help of muriatic acid, will prove that the before-mentioned arterial branch ramifies through the diplöe, reaching as far as the parietal bone. I have, for this reason, called it the Art. diplöetica magna, and I consider it to be an attempt of nature to reproduce, in man, the great diplöetic artery which some years ago I discovered in the large Edentata,^[6] as a branch of the very large occipital artery, and which, in these animals, penetrates the very dense diplöe of the bones of the cranium as far as the lamina cribrosa of the ethmoid, when it escapes, and is lost, with the olfactory nerves, in the mucous membrane of the nose.

Even when, as is sometimes the case, this branch of the human occipital artery passes right through the mastoid foramen, and actually reaches the dura mater, yet a comparison of the diameter of the artery as it enters, with that of the artery as it makes its exit through the foramen, will show a very striking difference in size; the artery, as it makes its appearance at the inner side of the mastoid foramen, not having half the diameter that it possessed on its entrance into the foramen, and, even in these cases, it sends a very considerable off-shoot to the diplöe.

 

Ligamentum teres.

It is said in most works on anatomy, that this ligament serves to conduct nutritive blood-vessels to the head and neck of the femur. I venture to doubt this general assertion, on the strength of isolated injections of the arteria obturatoria, under the pectineus muscle. These injections have proved, that all the capillary vessels in the ligamentum teres are, at the point where this latter is inserted into the oval depression on the head of the femur, reflected back again into veins, forming a large number of fine capillary loops, which form a very interesting object. When a vertical section of this ligament is made, no arterial vessel can be singled out, passing from the ligament to the bony substance of the head of the femur; but if you inject the perforating artery, of which the nutritive artery of the femur is a branch, you will obtain a very satisfactory microscopical injection of the interior of the bone; and, in a vertical section of the injected femur, one may trace the vessels to the very insertion of the ligamentum teres itself, without finding a trace of even the minutest branch passing into it. Further there is no anastomosis between the vessels of the round ligament and those of the medullary cavity, which must have been the case were the blood-vessels of the former destined to nourish the frame-work of the reticulated interior of the head of the femur.

 

Arteria auditoria interna.

Perhaps the most important result which I have obtained from a long series of isolated injections, has been yielded by injecting the internal auditory artery in man and other mammals; but this artery is so very small that it is quite impossible to introduce into it even the smallest injection tube, so that it is necessary to proceed to inject it in another way.

Place a ligature round the basilar artery, immediately in front of the origin of the internal auditory, just behind which the basilar artery may be easily fitted with an injection tube of tolerable dimensions; the injection being then prevented by the ligature from penetrating far into the basilar artery, must pass along into the auditory branch with all the requisite force. Next inject, in the same subject, the middle meningeal artery, with a differently coloured injection; both these injections must be composed of very fine materials. The investigator will now perceive that the labyrinth is supplied by the auditory artery, while the surrounding substance of the petrous bone is supplied by branches of the meningeal.

I shall not now enter into more details; these I reserve for another occasion; but, I may state that this independence of the circulations of the labyrinth and of the petrous bone, will account for the very interesting observations made by several French surgeons, and proved by many convincing pathological preparations, in my osteological collection, that a caries temporum may corrode away almost the whole of the petrous bone, without destroying the sense of hearing; and that the cochlea of a human ear, together with the vestibulum, may be exfoliated through a like caries, just as if prepared by the skilled hand of the anatomist, because the two having separate and independent circulations, each may preserve its integrity apart for a long time.

I have in my possession a very neat looking cochlea, which was taken out, with a forceps, from the external auditory meatus of an otorrhoic patient by a friend of mine, who is Surgeon to a suburban district in Prague.

1. Arteria carotico-lingualis; mihi.
2. I do not care much to claim the right of priority in scientific questions. That some new fact has been demonstrated, is well; it matters not who was the happy demonstrator; but I may infer, as a proof of the feeble renown of Austrian science, that my discovery of the blood-vessels in the hyaloidea of reptilia and amphibia, made when I was a young man (Med. Jahrbücher des Osten. Staater, Band 15) had not reached England when Mr. J. Quekett wrote bis "Observations on the vascularity of the Capsule of the Crystalline Lens, especially in certain Reptilia." (Trans. Microscop. Soc. of London, Vol. III. 1850).^[3] I made the first injection of the Hyaloidea of Coluber and Rana in the year 1831. The preparations are now in the Anatom. Museum of our University, and duplicates were sent in 1832 to Prof. Retzius in Stockholm, and 1837, to Prof. T. Müller in Berlin.
3. In a note to me, Prof. Hyrtl adds, that in all the Saurians and Chelonians there is no vascular hyaloidea, and that even among the amphibia, the Sozura—(Salamander, Triton, Amphuima, &c.) have a bloodless hyaloid. Professor Quekett erred in mistaking the hyaloidea for the capsule of the lens. In the frog the lens is very large, and the vitreous humour very small, so that in spirit specimens it almost disappears, and then the hyaloid membrane embraces the posterior portion of the lens so as to be easily mistaken for a capsule.
4. In a note Prof. Hyrtl says—The branchial clefts are very long and narrow in all clupeid fish, and the fringes on the convex border of the branchial arches are of so delicate an organization and possess such an extremely fine capillary network, that all the clupeid fish die the instant they are taken out of the water. Prof. Hyrtl suggests that hence the origin of "As dead as a herring."

   [The only objection to this explanation which occurs to us is that, as all who have seen herrings caught, know very well, the fish do not die the instant they come out of the water; nor indeed sooner than many other fish.—Eds.]

5. Denkscbriften der K. K. Akademie der Wissenschaften, Wien. 10 Bd. pag. 47, "Ueber die acccssorischen Kicmenorgane der Clupeaceen."
6. Vide "Ueber das Gefässystem der Edentaten." Denkschriften der Kais. Acad. Wissenchaft. Wien. vol. vi. 1854.