The Zoologist/4th series, vol 4 (1900)/Issue 709/Editorial Gleanings
EDITORIAL GLEANINGS.
In the 'Journal of the South-Eastern Agricultural College,' Wye, Kent, No. 9, issued in April last, Mr. F.V. Theobald has contributed an instructive article on "Diseases caused by Horse Worms and their Treatment." The following appear to be the major pests to the Horse:—
Amongst insects the Horse has several foes, including four species of Bot Flies. One of these flies, so far unidentified, forms warbles or tumours under the skin, like the Ox Warble. Probably this is Hypoderma silenus, but it is by no means common in this country; Mr. Theobald only remembers having seen one Horse attacked by it. The other Warble Flies live as parasites in their larval state inside the stomach and intestines (Gastrophilus equi, G. hæmorrhoidalis, and G. nasalis), where the bots cause annoyance and loss of condition, but seldom death. Lice of three species also annoy Horses turned out to grass, namely, the piercing-mouthed Hæmatopinus macrocephalus, or the Large Horse Louse, and two smaller species related to the Bird Lice, known as Trichodectes pilosus and T. pubescens, the former being the one most frequently seen, and is one of the three causes of that disfiguring rubbing of the tail. Numerous Diptera, such as the Gad Fly (Tabanus bovinus and T. autumnalis), Brimps (Hæmatopoda pluvialis), and others, suck their blood; whilst the Forest Fly (Hippobosca equina) causes annoyance in a few localities by tearing the hair and irritating the skin generally.
The three forms of "scab" or "mange" are also found on the Horse, caused by Sarcoptes scabiei v. equi, Psoroptes communis v. equi, and Symbiotes communis v. equi, mainly on weakly and ill-kept stock.
Amongst the vermiceous pests of the Horse we find representatives of the three great groups: Cestoda, or Tapeworms; Trematoda, or Flukes; and Nematoda, or Round Worms; but in this country the two former are rare and comparatively unimportant, for the loss they account for is slight. On the other hand, the Nematoda, or Round Worms, often are the cause of serious mortality, especially in young animals.
The Tapeworms found in the Horse are Tænia perfoliata, T. mamillana, and T. plicata. All three are uncommon, and do not seem to have occasioned any loss, nor do they seem to cause much inconvenience to their host. The two first-named species live in the intestines, but T. plicata is also said to be found in the stomach. Although uncommon in this country, Tæniæ are often abundant in the Horses in Russia and Germany. Tænia perfoliata, the commonest species, infests the cæcum and small intestine, sometimes the colon. It is a small worm, seldom reaching more than two or three inches in length—Rudolphi records it as reaching 80 mm.; the head is provided with four suckers, and, like the other two species, is devoid of hooks; the proglottides are thick and short, and the colour creamy white.
Nematodes we find in all parts of the body. This group of worms, which contains so many parasites, is of much importance to those interested in Horses and Horse-breeding in all parts of the world, for they are often the cause of serious epizootic attacks, occasioning very considerable loss. These Round Worms are particularly plentiful in the intestines of the Horse, where perhaps they cause the gravest functional disturbances; but they also invade the kidneys, eyes, blood-vessels, serous membranes, skin, &c.In Europe our chief pests are intestinal in habit, often causing great mortality in foals. The following are those which are most prejudicial to the health of the host, and which may be considered general equine pests:—
(Sclerostomum armatum, S. rubrum, and S. tetracanthum.)
Two species of so-called "Red Worms" are well known in the Horse, but observations made tend to show that we have evidently three species to deal with, for the common Small Red Worm, usually taken to be the S. tetracanthum of Diesing, does not agree with the detailed description of that species, which Mr. Theobald has observed only twice in England. He has therefore proposed provisionally the name rubrum for this Small Red Worm, as a distinct species from the one described by Diesing.
(Oxyuris curvula and O. mastigodes.)
The Maw Worm (Oxyuris) is a very prevalent equine pest, but, as far as can be gathered, it only occasions slight functional disturbances in digestion, and violent burning and itching sensations in the rectum and around the anus. When present in large numbers the Maw Worms nevertheless cause emaciation, and cannot be otherwise than prejudicial to their host.
(Ascaris megalocephala.)
This is perhaps one of the best known worms in the Horse on account of its size, the female often reaching 14 in. in length, and the male from 6 to 10 in. It is a special parasite of Horses. In colour it is yellowish white and rigid; the oral region is restricted off from the body, and provided with three lips with teeth on their free margin. The ova are globular, and are produced by hundreds, and are passed out in the host's excreta; numbers also come away with the female worms that are frequently passed by the Horse.
(Filaria papillosa of Rudolphi; the F. equina of Abildgaard.)
Although seldom of fatal import, this Threadworm is often present in the peritoneal cavities of the Horse, Ass, and Mule. In one instance as many as would fill a basket (how large we are not told) were extracted from the thoracic cavity of a Horse by Menges, lungs and all being invaded.
Two species of Spiroptera are found in Horses, living in the stomach, namely, Spiroptera megastoma (Rud.) and S. microstoma (Sehn), They are both found in the right sac of the stomach. It is not probable that the second species is at all common, but the former is; neither, as far as can be learned, causes any serious functional disturbances; but the former, if in large numbers, might easily become dangerous.
We have received the Annual Report (1899) of the Millport Marine Biological Station. "The station is now in a position to supply sets of beautiful marine zoological specimens at moderate charges to private individuals, as well as to schools and other institutions. As science is now receiving so much attention in school training, it is hoped that such sets may ere long be possessed by every well-equipped school."
At the request of the Vice-Chairman, Dr. Gemmill, repeated and persistent efforts were made during last winter to fertilize the eggs of the Limpet (Patella vulgata, L.), and to rear the young up through all their stages, but without success. Fertilization of the ova was easy enough, and the keeping of the little brown, opaque, free-swimming larvæ up till the twelfth or fourteenth day, but at that age they invariably died off, excepting in the case of one culture, in which a few lived till the twenty-first day. From the sixth day onwards the water in the hatching-jars was found swarming with Infusorians, which soon devoured the unfortunate larvæ. Similarly, attempts were made, with varying success, on fertilized ova of crustaceans, molluscs, worms, and fishes, as well as on unknown ova obtained from the tow-nets. Failure, when it did occur, was doubtless largely due to the inability to imitate sufficiently the natural conditions of the sea, even by constant gentle movements in the hatching-vessels, and by continual circulation of pure sea-water. With the facilities at command many perfectly normal and healthy batches of Echinus larvæ were successfully hatched out, and the interesting changes in their development carefully watched from day to day. The young of the common Urchin (Echinus esculentus, L.) is a favourite with students of embryology, as its transparency makes it easy to follow the successive changes in structural development, even when alive and active. Some exceptionally good fertilizations of this echinoderm were obtained early in May by Dr. Thomas H. Bryce, Queen Margaret College, University of Glasgow, from which he has prepared microscopic sections, the photographs of which, taken by Dr. J.H. Teacher, have been made into a very valuable series of lantern slides. A finely mounted set of these slides has been presented to the Station by the gentlemen named, and by means of the lantern given by Mr. Paul Rottenburg, of Glasgow, they can now be used for demonstration purposes.
Mr. W. Wells Bladen has taken a specimen of the Fresh-water Mussel (Dreissensia polymorpha) containing a very beautiful and perfect pearl. This shell was found in a large colony of the species in the North Staffordshire Canal, near Rugeley. The pearl attached to it is almost spherical in shape, and has a small protuberance at one side; it is 2 mm. in diameter, and is very pure in colour. This is said to be the first recorded instance of a pearl being found in this mollusc. The shell is figured in the Ann. Rep. and Trans, of the "North Staffordshire Field Club," 1899-1900, vol. xxxiv.
At Stevens' Auction Rooms two more eggs of the Great Auk were recently disposed of. One—an unrecorded egg—sold for three hundred and fifteen guineas, and the other egg for one hundred and eighty guineas. They were both bought by Mr. Gardner, of Oxford Street.
The 'Banffshire Journal' of June 5th last has published a letter received from Mr. J. A. Harvie-Brown, relating to Elvers, Eels, and Smolts. The following are extracts from same:—
"It is certain Elvers are largely consumed by Brown Trout for a few days. Soon after that, worm becomes the deadly bait. Why? Well, worm in low clear water, after the run of Elvers, becomes a necessary purge to Trout after the Eel 'stodge.' At least, I believe this to be the case—just as grass is an occasional vomit for a Dog.
"If Elvers are largely consumed by Brown Trout, they are also largely consumed by Sea-Trout, Grilse, and probably also by Smolts. What are known among Sea-Trout as Finnocks, at the mouths of our East Coast rivers in April, May, &c, are the Grilse of the Sea-Trout, which went down the previous year as Smolts, which went up as Grilse or Sea-Trout, do not breed, but attain a growth of up to, say, half a pound, or less, and come down again along with the Smolts of the Salmon. Their time so far is known to legislators, because fishing for Finnocks is prohibited whilst the Salmon Smolts are descending—i.e. about 15th May. The baskets of Sea-Trout and Finnock made in the spring months on the East Coast of Scotland—at Ythan, Deveron, Findhorn, &c.—are either down-run Kelts or unspawning Grilse of the Sea-Trout; or rapidly-grown Smolts of the Sea-Trout; or Smolts of the Sea-Trout which have remained two years in the fresh-water streams, after putting on the silver. Thus we find Par ¼ lb. weight, but Smolts in silver often three inches long only, and others seven inches long. These, I take it, are the young of different hatchings, the larger of which are the progeny of older Salmon; the larger and smaller Par in the same way.
"Now, if Brown Trout feed—'stodge'—on Elvers, they lie in wait for them, because Brown Trout are not strictly migratory; but if Smolts and Sea-Trout Grilse also feed largely on Elvers—as I feel sure they do—they, being anodromous or migratory, come down in bulk to meet the Elvers. The first appearance of Elvers on any reach of water (on Deveron) wakes up the migratory instinct at once, and, acting almost like ground-bait, sets the Smolts and Sea-Trout Grilse—aye, and Salmon Kelts, too—on the move seaward. Thence the well-known name, 'A weel-mendit kelt.'"
We are glad to see from 'The Scottish Geographical Magazine' for June that it is proposed to organize and equip a Scottish National Antarctic Expedition, which will co-operate with the German and British expeditions now being fitted out, and devote its attention more especially to physical and biological oceanographical researches, and to geology and meteorology.
The Scottish vessel will be one of the ordinary Norwegian or Scottish type of whalers of about 500 tons, 130 ft. long, and steaming seven to eight knots. A ship of this size will have ample accommodation for thirty-seven all told. The proposed staff includes six scientists and five ships' officers, and a crew of twenty-six. The ship will proceed from Scotland on August 1st, 1901, to Port Stanley, in the Falkland Islands, which will form the base for operations in the Antarctic regions. She will proceed southward by Weddell's track in 30° W. This route has never yet been tried seriously with a steamer. Weddell, in 1823, penetrated far south with two sailing ships, one of 120 tons and one of 65 tons; Bellinghausen also was successful a little farther eastward. Ross, with sailing-ship, failed, but Larsen, with a steamer, reached 68° S. in about 60° W. The Dundee whalers, in 1892 and 1893, being on commerce bound, were chiefly occupied securing Seals, and, since these abounded in the vicinity of the Circle, they had no need to go farther south. There is little doubt that the ice can be penetrated by such a vessel as that above mentioned.
Mr. William S. Bruce will take command of the expedition with a whaling captain under him and four other officers; a naturalist will be permanently attached to the ship, and will take charge of and carry on the scientific work there during the leader's absence with the wintering party. The land party will land in a high latitude on the east coast of Graham's Land, and the ship will return northward for the winter.
This work was published before January 1, 1929, and is in the public domain worldwide because the author died at least 100 years ago.
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