PHYSIOLOGY OF DIGESTION IN BLATTIDAE Sis) 
I attempted to use the soluble fat ethyl butyrate in a series of 
experiments similar to those described. In every case the acidity 
at the end of the experiment was about the same as that at the 
beginning, so there was evidently something toxie about the fat 
which resisted the enzyme, as other workers have found in 
vertebrates. 
Absorption in the crop is not a generally accepted view at the 
present day. No author of the last decade has spoken decidedly 
in its favor; nevertheless, I believe it regularly takes place and 
is of very large importance. Plateau was the first careful in- 
vestigator in this field; he concluded that in the form he studied 
a large part of the absorption of food occurs in the crop. Jousset 
de Bellesme found similar results in his experiments with sugar, in 
which he seemed to prove that sugar entered the cells from the 
lumen by diffusion. Both of the latter investigators found evi- 
dence that starchy food does not soon pass into the stomach, but 
is retained by the crop to be digested and absorbed. In ecriti- 
cism, Cuénot and Biedermann have sought to disprove this by 
assuming that there is a continual passage into the stomach and 
subsequent rapid absorption; therefore but little is ever present 
in the stomach’s lumen. 
Cuénot observed that the cells of the crop have a chitinous 
intima, while those of the stomach do not, so he reasoned that 
absorption should only occur in the stomach. His conclusions 
were not entirely verified by experimental work, so they cannot 
be accepted unreservedly. He fed colored fluids to Blatta, and 
found them after several days present in the stomach only. I 
have never been able to repeat this experiment, and I believe 
we must conclude that some of the colored matter he fed was 
absorbed by way of the crop during the several days the experi- 
ment lasted, so none was present there when the animal was 
dissected. 
Petrunkevitch in 1898 made a series of experiments in which 
he starved cockroaches twenty-four hours, fed them lumps of fat, 
and killed them after varying lengths of time. Large amounts of 
fat were found in the epithelial cells, and progressively less with 
longer and longer periods afterward. The periods of time used are 
