DEGENERATION AND DEATH 1N ENTAMG@BA RANARUM. ot 
Physiological Degeneration and Death in 
Entameba ranarum. 
By 
Cc. Clifford Dobell, 
Fellow of Trinity College, Cambridge; Balfour Student 
in the University. 
With 5 Text-figures. 
Iy the following pages, I wish to call attention to some re- 
markable events which I have observed in the life-history of 
Entamceba ranarum Grassi, an organism which I have been 
studying for some time, and whose life-cycle—so far as I had 
succeeded in following it—I have already described in a 
previous paper (2). I will divide my remarks into two sections 
—I, a description of the phenomena actually observed, and 
II, a discussion of their significance. 
Je 
I have given elsewhere (2) a detailed description of E. 
ranarum, but I must here briefly refer to the structure of 
an ordinary individual once more. A typical amoeba, taken 
from the rectum of a frog or toad, measures—roughly speak- 
ing—20-30 uw in diameter, and has a nucleus whose diameter 
is about 6. For comparison with the forms I am about to 
describe, I have given a figure of an ordinary organism (text-fig. 
A, 1), showing the structure of the nucleus. The latter has 
most of its chromatin in the form of granules arranged peri- 
pherally, so that it has an annular appearance in optical section. 
Now I occasionally found forms which differ from these 
