30 BLOOD CORPUSCLES. 



granules. If the action of the acid has been prolonged, each 

 corpuscle appears to consist of two parts a distinctly gran- 

 ular mass, which immediately surrounds the nucleus, and a 

 bright transparent circle, with sharp outline, within which 

 that body is inclosed. The nuclei are furrowed in such a way 

 that their form is very variable, and, if the action lias lasted 

 long enough, they look as if actually split into smaller par- 

 ticles. The colored corpuscles again become smooth, swell out 

 somewhat, become cellular in their contour, just as after the 

 addition of water, each showing an oblong granular nucleus, 

 which is at first smooth, subsequently uneven and rough. 

 Many of the blood disks return to their original elliptical form. 

 All eventually lose their color, but possess, even when entirely 

 colorless, a much more distinct contour than those which have 

 been acted upon by water. Occasionally, it happens that the 

 nucleus becomes stained with coloring matter, and assumes a 

 yellow tint. In human blood, the colorless corpuscles exhibit, 

 after the action of acetic acid, the appearance of globular bodies, 

 in which two, three, or more small shrunken nuclei are visible. 

 The colored disks lose their stellate form and their coloring 

 matter, but their outlines are still distinct. 



Action of Alkalies. If a salt solution preparation is irri- 

 gated with an alkaline liquid, whatever be the source of the 

 blood used, the colorless corpuscles at first swell, and then 

 rapidly disappear. The colored disks also swell out at first 

 those of mammalia becoming often what German authors have 

 designated napformig (cup-shaped) ; eventually they lose 

 their color and disappear. 



Action of Boracic Acid. We have now to describe a 

 reaction which, especially in the blood of the newt, is of im- 

 portance, as serving to illustrate the intimate structure of the 

 colored blood disk. The action of a two per cent, solution of 

 boracic acid on the colorless corpuscles in general, and on the 

 blood disks of mammalia, does not differ from that of other 

 weak acids. If, however, a salt preparation of newt's blood, in 

 which the colored corpuscles have already sunk, is irrigated 

 with the solution in question, we observe that those bodies 

 swell and acquire a circular contour, showing, at the same time, 

 a pale oval nucleus. It is no\vseen that, as the disk grad- 

 ually pales, the nucleus becomes more and more spheroidal 

 and yellow, while, at the same time, it increases in size. At 

 first it is smooth, subsequently uneven. Here and there cor- 

 puscles are met with in which the yellow central body (zooid 

 of Briicke) is not round, but beset with processes which stretch 

 like rajs towards the periphery. Occasionally, it can be made 

 out that the processes are withdrawn, so that the yellow centre 

 acquires a roundish form. The zooids eventually lose theif 

 central position, and if the preparation is protected from evapo- 



