1S96.] MICROSCOPICAL JOURNAL. 267 



a live specimen. There are a number of different 

 species of Amoeba, if you can find more than one, com- 

 pare and draw them all. 



8. Physiology of Amoeba. — It is not easy to demon- 

 strate all of the functions of the cell upon Amoeba, but 

 a summary of them may be conveniently made here 

 and as many of tliem should be observed as possible. 

 It is often impossible to find specimens that illustrate 

 desired points at a given time, but they are often met 

 incidentally vsrhile in the pursuit of other items, and can 

 then be watched. The most conspicuous function of 

 Amoeba is iJiotion. This takes several forms, such as 



(1) cyclosis, or the circulation of the protoplasm ; 



(2) contracMon of the vacuole ; and (3) locomotion — 

 by means of the pseudopodia. A careful study of the 

 latter will show that it is in the ectoplasm that the mo- 

 tion takes place first, the endoplasm flowing into it as 

 the pspudopodium enlarges. Occasionly you can catch 

 a specimen i^n the act of engulyliing his food ; this takes 

 place by the formation of a pocket in the ectoplasm 

 which gradually encloses the food and finally shuts it in- 

 to the endoplasm. After a time the indigestible residue 

 of the food is rejected by the inverse process. There is 

 no definite part used in either of these processes. It is 

 the general belief of biologists that Amoeba has powers 

 of sensation, but the illustration of this can be better made 

 on Paramaecium and Vorticella. Occasionally specimens 

 of Amoeba are found that appear to have aline crossing 

 them in the middle. These ought to be kept in 

 sight and after a brief interval you will find that the 

 line deepens till it cuts the animal in two; it is by this 

 process of fission, a mode of the general function of 

 reproduction, that Amoeba multiplies. The two small 

 Amoebae feed and grow to the size of the original and 

 then the process repeats itself. It should be remem- 



