BY DR. KLEIN. 25 



striction of the base of each of these prominences it gradually 

 separated from the rest of the cell. One of them, after sei>:i ra- 

 tion, sent out a process ; in the other, no alteration of form 

 could be observed. It is probable that the forms a and It are 

 the offspring of c. 



On the warm stage, division can also be observed in the first 

 and second variety of colorless corpuscles. Thus, for example, 

 it sometimes happens that the process described only results 

 in actual separation by rupture of the filament. In other cases 

 a corpuscle undergoes division by a process of cleavage, pre- 

 ceded by the repeated formation, disappearance, and reappear- 

 ance of furrows. In all cases of real division it is to be 

 observed that the 3 r oung cells produced exhibit very active 

 movements, changing thereby in form and place. 



Colorless Corpuscles of Man. The mode of examining 

 the colorless corpuscles of other classes of animals is similar 

 to that above described. It is, however, necessary to add some 

 observations as to the characters which these bodies present 

 in human blood. A drop of blood, taken from the finger, is 

 placed between two cover-glasses, as above described, and 

 examined on the warm stage at a temperature of 38 C. The 

 Imncuui-caLarlessL corpuscles are smaller than those of the newt, 

 and exhibit much less variety in their appearance. They are 

 either quite pale, or they contain a variable number of dark 

 granules. The movements are less active than those of newt's 

 blood, but sometimes are comparable with them. When they 

 are more active than usual, the mode in which their processes 

 are thrown out and retracted, and the characters of their pro- 

 gressive movement correspond with the descriptions already 

 given. On one occasion I have observed movements which 

 were even more lively than those commonly seen in the newt, 

 and resembled those of rhizopods in the extreme rapidity with 

 which the successive protrusion of processes, and corresponding 

 interstitial fluxion of the protoplasm occurred. This happened 

 in the case of a patient suffering from hemorrhagic anaemia. 



Feeding of Colorless Corpuscles. We have now to 

 stucVy the faculty possessed by the colorless corpuscles of 

 taking, by virtue of their amo3boid movement, solid particles 

 into their substance. For this purpose we employ either finely- 

 divided fatty substances or coloring matters. The subject is 

 of great interest in relation to the mode in which amoeboid 

 cells take in nourishment. To the histologist it is further of 

 importance, as affording him a means by which to mark indi- 

 vidual corpuscles, so as to follow them in their wanderings 

 through the organism. The materials used are the following: 

 a. Vermilion. This is prepared by prolonged trituration in 

 a half per cent, solution of common salt. b. Carmine. Car- 

 mine is dissolved in as little liquor- ammonias as possible, in a 



