400 ELDON W. SANFORD 
was absorbed by the stomach and intestine. Perhaps Blan- 
chard’s conclusions of 1849 may be due to poor definition of 
tracheal lumen and peritracheal cells on his slides. My experi- 
ments support Petrunkevitch in stating that there is no evident 
peritracheal circulation in the cockroach. 
In conclusion, I wish to thank Professor Petrunkevitch, under 
whose direction the work was done. I wish, too, to thank Pro- 
fessor Mendel for his advice concerning some of the experiments, 
and Professors Osborne and Mendel for some of the reagents 
used; also Mr. W. 8. Sturges for assistance with the titrations. 
SUMMARY 
1. The crop is the principal organ of digestion in the cockroach. 
Its enzyme splits fats to soluble products. The progress of 
digestion may be observed by giving food containing indicator 
stains. Digestions may be carried on outside of the body, and 
quantitative estimations of the amount of digestion may be 
made by titration. Such tests show that the crop is at least 
three times as active as the stomach in fat digestion. 
2. The crop is the principal organ of absorption of fats. The 
process is rather slow and reaches a maximum two days after the 
fat is eaten. The absorption of one large meal may take two 
months. All cells of the epithelium of the crop can absorb; the 
cells may store globules of fat until it is needed. 
3. The crop is an important organ for storage of food; it may 
store enough to supply the needs of the animal more than two 
months. 
4. The gizzard has an important sphincter action, and may 
withhold food from the stomach several days. The sphincter 
action resides in the folds which protect the passage from the 
gizzard into the stomach. 
5. The needles on the six significant folds or cushions of the 
posterior region of the gizzard are moved by special muscle 
fibrils and tendons derived from long strands of striated muscle. 
The function is difficult to ascertain, but possibly they aid in 
moving food through the gizzard. 
