380 



PROF. TH. W. ENGELMANN. 



in consequence of the appearance and disappearance of 

 processes which, although taking on very various forms, 

 almost always remain unfused with one another. As these 

 processes fasten themselves to fixed bodies, they can, by short- 

 ening themselves, draw the remaining protoplasm after them, 

 and produce a movement of translation. The rapidity with 

 which they can do this varies with the particular body and its 

 surroundings, but always remains microscopic. A velocity of 

 0*5 mm. a minute which is sometimes attained by an Amoeba 

 may be considered as exceptionally rapid. The force with 

 which amoeboid movement takes place may be regarded as of 

 a quite important value. The wandering cells of the frog's 

 cornea, for instance, move between the fibrillse and lamellae 

 and between the other epithelium cells, which in doing so they 

 must push apart from one another. 



Fig. 1 shows the different forms {a — p) which the same 



Fig. 1. — A colourless blojod-corpuscle of a frog under the influence of 

 {a — m) a gradually increasing temperature, which [n—p) subsequently 

 diminishes. 



