388 : ELDON W. SANFORD 
Among the earliest is that of Miall and Denny, who state in 
their text-book that the digestive products pass from the lumen 
through the protoplasm of the cells to the body cavity. We 
now know that the protoplasm has a selective absorptive action. 
Petrunkevitch’s opinion is, in brief, that in the stomach only 
the oldest cells, between the regenerating places, can absorb. 
Thus only a part of the inner surface of the stomach epithelium 
is capable of absorption. Digestion is considered as not very 
powerful here, but occurring mostly in the crop. The coeca are 
described as being structured similarly to the stomach and capa- 
ble of absorption, but in less amount, for their function is mostly 
secretory. 
VanGehuchten has described in one form a ring of special 
absorbing cells. This probably is not present in most insects. 
Holtz has found that in Nematus the cells send out pseudopodia 
around the food and absorb it gradually. The pseudopodia 
are said to be distinct histologically and physiologically from 
the globules of secretion which are formed at the ends of the 
cells. 
Cuénot found fat absorption in the posterior two-thirds of the 
stomach and in moderate amounts. The coeca are said to have 
a strong absorptive power. He thought the midgut was the 
only part: of the alimentary canal, capable of absorption. 
Steudel in his work on cockroaches showed that only the non- 
secreting cells of the stomach were capable of absorption, and 
not the cells which were undergoing a process of formation of 
secretion globules. The unspecialized or resting stage 1s con- 
sidered as an absorptive phase, which alternates in the cell with . 
a secretory stage. He found conspicuous absorption of fat in 
the stomach and some in the coeca. 
A great discussion has been waged over the question whether 
the stomach is the only organ capable of absorption. The ab- 
sence here of the chitinous wall present in all other parts of the 
alimentary canal has led many on a priori grounds to believe 
that here and here only is absorption possible. Cuénot in 1896 
stated that the stomach alone had the power of absorption- 
while the chitin of all other parts was impenetrable. Kowal; 
