14 BULLETIN 817, U. S. DEPT. OF AGRICULTURE. 
during the first day or two after the eggs are swallowed, the larvee 
that have migrated through the lungs begin to pass out of the body 
in the feces about 9 days after infection and have usually all or prac- 
tically all been eliminated in less than 3 weeks after infection. Dur- 
ing their stay in the body they may increase in size from an origi- 
nal length of 0.2 to 0.3 mm. to a length of nearly 2.5 mm. (Stewart), 
most of them, however, reaching a length not exceeding 1.75 mm., and 
some being not more than 1 mm. long when eliminated in the feces. 
Stewart (1916a) remarked upon the occurrence of larve in the 
spleen. We have occasionally observed larve in the spleen, 2 being 
present in the spleen of a mouse examined 23 days after infection, 8 
in the spleen of a mouse examined 19 days after infection, and 1 in 
the spleen of a mouse examined 9 days after infection—in this case 
measuring 0.36 mm. in length. As a rule, however, the spleens of our 
experimental animals, which were commonly but not always ex- 
amined, showed no larve, so that this organ may be considered an 
unusual location. In one case a larva was found in the thyroid gland 
of a mouse 23 days after infection. In another mouse 13 days after 
infection larvee were found under the peritoneum in various places 
in the abdominal cavity, including the Fallopian tubes. Probably the 
larvee occur rather infrequently in the spleen, thyroid, and under the 
peritoneum of the abdominal cavity, but in our examinations, except 
in the case of the spleen, we rarely looked for them in these places. 
The kidneys have been examined repeatedly, but no larve have been 
found in them. 
~ It has been suggested that the larve migrating from the intestine 
reach the liver by way of the portal vein, continue to the heart in the 
hepatic veins and vena cava, and from the heart to the lung in the 
pulmonary artery, and it is possible that most of the larvee follow 
this course. Evidently, however, in view of their occurrence in the 
spleen, thyroid, etc., some of the larve at least may migrate along 
other paths. How they get to the spleen, thyroid, and under the 
peritoneal lining of the abdominal cavity has not been explained. 
The possibility is not excluded that in their migrations from the in- © 
testine some of the newly hatched larve are carried in the lymphatics 
more or less directly to the heart and reach the lungs without passing 
through the liver. Perhaps some of these larve, together with others 
that pass very rapidly through the liver and are soon carried in the 
portal circulation to the heart and lungs before they have increased 
much in size, get into the pulmonary veins, notwithstanding the 
intervening capillaries, are returned to the heart, and are then dis- 
tributed to various parts of the body. 
Since the foregoing was written more than a year ago, two papers 
by Yoshida (1919) have come to hand. In the latter of these papers 
Yoshida gives the results of experiments from which he concludes 
