233 
me to answer these three questions in the negative!), at the same 
time stating the reasons which originally led me to answer them 
affırmatively. 
1) Dothe spherical bubble-like structures to be found 
in and outside the cytoplasm of the gas gland cells in 
serial sections of active glands represent gas bubbles 
in process of formation? 
Extraordinary as it may seem, in view of the hot controversy 
between Nuspaum and Reis (9, 10, 11, 12) on the one hand, and 
JAEGER (4, 5, 6, 7, 8) on the other, respecting the nature of these 
vacuole-like spaces, yet, so far as I am aware, no one has up to the 
present investigated the living cells of the active gland in order to 
settle this dispute. Moreover few enquiries could be more easy, since 
if oxygen bubbles exist inside the gland cells these must of necessity 
be more conspicuous even than air bubbles in water, seeing that the 
refractive indices of oxygen and protoplasm differ more from each 
other than do those of air and water. I employed Pollack for all 
observations made on the living active gland, the fish in every case 
having been weighted for six hours. I first teased up in succession 
the cells of the living active glands of at least 4 fishes and examined 
them in normal salt solution under a 2 mm oil immersion. Only on 
one occasion did I detect a gas bubble inside a cell and this I am 
convinced was an accidental formation. All the other cells exhibited 
no trace of gas contents. These living cells, however, appeared to be 
full of refringent granules, somewhat resembling zymogen granules, 
and large yellowish spheres, these latter being occasionally set free 
from the cells at the periphery. The longer these teased up pre- 
parations were kept, the more abundant become these yellowish spheres. 
which after arising in the cytoplasm, were freely budded- off, so to 
speak, from the cells, often forming foam-like masses. They very 
closely resembled, indeed, the pale bubbles which are set free from the 
periphery of a degenerating Paramaecium. I treated some of these 
living preparations with strong sodium carbonate and a 5°/, solution 
of pyrogallic acid run under the cover-slip but could not detect for 
certain any free oxygen present in these pale spheres, though the 
tissues were well soaked in the fluid and the solution outside the 
1) I have already stated this evidence in a paper recently read 
before Section I, British Association for the Advancement of Science, 
Portsmouth, September 1911. 
