602 VERTEBRA TED ANIMALS. 



place ; but it is in some respects preferable to dilute the liquid 

 with a small quantity of Goadby's solution, its strength being so 

 adjusted as not to produce any endosmotic change of form in the 

 corpuscles. But it is far simpler to allow such films to dry, with- 

 out any cover, and then merely to cover them for protection ; 

 and in this condition the general characters of the corpuscles can 

 be very well made out, notwithstanding that they have in some 

 degree shrivelled by the desiccation they have undergone. And 

 this method is particularly serviceable, as affording a fair means 

 of comparison, when the assistance of the Microscopist is sought 

 in determining, for Medico-legal purposes, the source of sus- 

 picious blood stains; the average dimensions of the dried blood- 

 corpuscles of the several domestic animals, being sufficiently 

 different from each other and from those of Man, to allow the 

 nature of any specimen to be pronounced upon with a high de- 

 gree of probability. 



417. Simple Fibrous Tissues. A large proportion of every 

 animal fabric is made up of simple fibres, whose function is to 

 hold other parts together, or to serve as cords for the communi- 

 cation of movement. A very beautiful example of a fibrous 

 tissue of this kind, is furnished by the membrane of the com- 

 mon Fowl's egg, which (as may be seen by examining an egg 

 whose shell remains soft for want of consolidation by calcareous 

 particles) consists of two principal layers, one serving as the 

 basis of the shell itself, and the other forming that lining to it, 

 which is known as the membrana putaminis. The latter may 

 be separated, by careful tearing with needles and forceps, after 

 prolonged maceration in water, into several matted lamellae re- 

 sembling that represented in Fig. 316 ; and similar lamellae may 

 be readily obtained from the shell itself, by dissolving away its 

 lime by dilute acid. The simply fibrous structures of the body 

 generally, however, belong to one of two very definite kinds of 

 tissue; the "white" and the "yellow," whose appearance, com- 

 position, and properties are very different. The white fibrous 

 tissue, though sometimes apparently composed of distinct fibres, 

 more commonly presents the aspect of bands, usually of a 

 flattened form, and attaining the breadth of l-500th of an inch, 

 which are marked by numerous longitudinal streaks, but can 

 seldom be torn up into minute fibres of determinate size. The 

 fibres and bands are occasionally somewhat wavy in their direc- 

 tion ; and they have a peculiar tendency to fall into undulations, 

 when it is attempted to tear them apart from each other (Fig. 

 317). This tissue is easily distinguished from the other, by the 

 effect of acetic acid, which swells it up and renders it transparent, 

 at the same time bringing into view certain oval nuclear cor- 

 puscles. It is perfectly inelastic ; and we find it in such parts as 

 tendons, ordinary ligaments, fibrous capsules, &c., whose function 

 it is to resist tension without yielding to it. The yellow fibrous 

 tissue exists in the form of long, single, elastic, branching fila- 



