There is considerable difficulty in removing mounted specimens of algaj from paper, and therefore a small portion preserved on mica should accompany each specimen, enclosed for safety in a small envelope fastened at one corner of the sheet of paper. Filamentous diatoms may be mounted like ordinary seaweeds, and, as well as all parasitic alga;, should whenever possible be allowed to remain attached to a portion of the alga on which they grow, some species being almost always found parasitical on particular plants. Ordi nary diatoms and desmids may be mounted on mica, as above described, by putting a portion in a vessel of water and exposing it to sunlight, when they rise to the surface, and may be thus removed comparatively free from dirt or impurity. Owing to their want of adhesiveness, they are, however, usually mounted on glass as microscopic slides, either in glycerin jelly, Canada balsam, or some other suitable medium.
Lichens are generally mounted on sheets of paper of the ordinary size, several specimens from different localities being laid upon one sheet, each specimen having been first placed on a small square of paper which is gummed on the sheet, and which has the locality, date, name of collector, &c. , written upon it. This mode has some disadvantages attending it: such sheets are difficult to handle ; the crustaceous species are liable to have their surfaces rubbed ; the foliaceous species become so compressed as to lose their characteristic appearance ; and the spaces between the sheets caused by the thickness of the specimen permit the entrance of dust. A plan which has been found to answer well is to arrange them in cardboard boxes, either with glass tops or in sliding covers, in drawers the name being placed outside each box, and the speci mens gummed into the boxes. Lichens for the herbarium should, whenever possible, be sought for on a slaty or laminated rock, so as to procure them on flat thin pieces of the same, suitable for mounting. Specimens on the bark of trees require pressure until the bark is dry, lest they become curled ; and those growing on sand or friable soil, such as Coniocyle furfaracca, should be laid carefully on a layer of gum in the box in which they are intended to be kept. Many lichens, such as the Verrucarias and Collcmacece-, are found in the best condition during the winter months. In mounting collemas it is advisable to let the specimen become dry and hard, and then to separate a portion from adherent mosses, earth, &c., and mount it separately so as to show the branching of the tluillus. Pcriusarice should be represented by both fruiting and sorediate specimens.
The larger species of fungi, such as the Agaricini and Polyporci, &c. , are prepared for the herbarium by cutting a slice out of the centre of the plant so as to show the outline of the pileus, the attachment of the gills, and the character of the interior of the stem. The remaining two halves of the pileus are then lightly pressed, as well as the central slices, between bibulous paper until dry, and the whole is then " poisoned," and gummed on a sheet of paper in such a manner as to show the under surface of the one and the upper surface of the other half of the pilens on the same sheet. As it is impossible to preserve the natural colours of fungi, the specimens should, whenever possible, be accompanied by a coloured drawing of the plant. Microscopic fungi are usually preserved in envelopes, or simply attached to sheets of paper, or mounted as microscopic slides. Those fungi which are of a dusty nature, like the Myxomycctcs, may, like the lichens, be preserved in small boxes, and arranged in drawers. Fungi under any circumstances form the least satisfactory portion of an herbarium.
Mosses when growing in tufts should be gathered just before the capsules have become brown, divided into small flat portions, and pressed lightly in drying paper. During this process the capsules ripen, and are thus obtained in a perfect state. They are then preserved in envelopes attached to a sheet of paper of the ordinary size, a single perfect specimen being washed, and spread out near the envelope so as to show the habit of the plant. For attaching it to the paper a strong mucilage of gum tragacanth, containing an eighth of it.s weight of spirit of wine, answers best. If not preserved in an envelope the calyptra and operculum arc very apt to fall off and become lost. Scale-mosses are mounted in the same way, or may be floated out in water like sea-weeds, and dried in white blotting paper under strong pressure before gumming on paper, but are best mounted as microscopic slides, care being taken to show the stipules. The specimens should be collected when the capsules are just appearing above or in the colesule or calyx ; if kept in a damp saucer they soon arrive at maturity, and can then be mounted in better condition, the fruit-stalks being too fragile to bear car riage in a botanical tin case without injury.
Of the Charaiece many are so exceedingly brittle that it is best to float them out like sea-weeds, except the prickly species, which may be carefully laid out on bibulous paper, and when dry fastened on sheets of white paper by means of gummed strips. Care should ba taken in collecting charse to secure, in the case of dioecious species, specimens of both forms, and also to get when possible the roots of those species on which the small granular starchy bodies or gemmaj are found, as in C. fragifcra. Portions of the fructification may be preserved in small envelopes attached to the sheets.
See Bentham, Proc. Linn. Soc. Land., 1869-70, p. xlvi. ; Johann Nave, Handy Book to the Collection and Preparation of Frcshwata and Marine Algcc, &c. , Lond. ; G. Kainann, Das Herbarium, Berlin , and Lasegue s Musee botanique do M. Benjamin Ddcsscrt, Paris, 1845.
HERBART, Johann Friedrich (1776–1841), was born of cultured parents at Oldenburg in 1776. He showed his bent towards philosophy while still a child, and after study ing under Fichte at Jena gave his first philosophical lectures at Gottingen in 1805, whence he removed in 1809 to occupy. the chair formerly held by Kant at Konigsberg. Here he also established and conducted a seminary of poedagogy till 1833, when he returned once more to Gottingen, and remained there as professor of philosophy till his death in 1841. His works were collected and pub lished in twelve volumes by Ids disciple Hartenstein (Leipsic, 1850-52).
Philosophy, according to Herbart, begins with reflexion upon our empirical conceptions, and consists in the reformation and elaboration of these, its three primary divisions being determined by as many distinct forms of elaboration. Logic, which stands lirst, has to render our conceptions and the judgments and reasonings arising from them clear and distinct. But some conceptions are such that the more distinct they are made the more contradictory their elements become ; so to change and supplement these as to make them at length tliinkable is the problem of the second pai t of philosophy, or Metaphysics. There is still a class of conceptions requiring more than a logical treatment, but differing from the last in not involving latent contradictions, and in being independent of the reality of their objects, the conceptions, viz., that embody our judgments of approval and disapproval ; the philosophic treatment of these conceptions falls to ^Esthetic.
In Herbart s writings logic receives comparatively meagre notice; he insisted strongly on its purely formal character, and expressed himself in the main at one with Kantians such as Fries and Krug.
As a metaphysician he starts from what he terms "the higher scepticism " of the Hume-Kantian sphere of thought, the beginnings of which he discerns in Locke s perplexity about the idea of sub stance. By this scepticism the real validity of even the forms of experience is called in question on account of the contradictions they are found to involve. And yet that these forms are "given" to us, as truly as sensations are, follows beyond doubt when we consider that we are as little able to control the one as the other. To attempt at this stage a psychological inquiry into the origin of these concep tions would be doubly a mistake ; for we should have to use these illegitimated conceptions in the course of it, and the task of clearing up their contradictions would still remain, whether we suc ceeded in our inquiry or not. But how are we to set about this task? We have given to us a conception A uniting among its con stituent marks two that prove to be contradictory, say M and N ; and we can neither deny the unity nor reject one of the contra dictory members. For to do either is forbidden by experience ; and yet to do nothing is forbidden by logic. We are thus driven to the assumption that the conception is contradictory because incomplete; but how are we to supplement it ? What we have must point the way to what we want, or onr procedure will be arbitrary. Experi ence asserts that M is the same (i.e., a mark of the same concept) as N, while logic denies it ; and so it being impossible for one and the same M to sustain these contradictory positions there is but one way open to us ; we must posit several Ms. But even now we cannot say one of these Ms is the same as N, another is not ; for every M must be both tliinkable and valid. We may, however, take the Ms not singly but together ; and again, no other course being open to us, this is what we must do; we must assume that N results from a combination of Ms. This is Herbart s -method of relations, the counterpart in his system of the Hegelian dialectic.
In the Ontology this method is employed to determine what in reality corresponds to the empirical conceptions of substance and cause, or rather of inherence and change. But first we must analyse this notion of reality itself, to which our scepticism had already led us, for, though we could doubt whether "the given" is what it appears, we cannot doubt that it is something ; the con ception of the real thus consists of the two conceptions of being and quality. That which we are compelled to "posit," which cannot be snblated, is that which is, and in the recognition of this lies the simple conception of being. But when is a thing thus posited ? When it is posited as we are wont to posit the things we see and taste and handle. If we were without sensations, i.e. , were never bound against our will to endure the persistence of a presentation, we should never know what being is. Keeping fast hold of this idea of absolute position, Herbart leads us next to the quality of the real. (1) This must exclude everything negative ; for non-A sub- lates instead of positing, and is not absolute, but relative to A. (2) The real must be absolutely simple ; for if it contain two d ter-
