22 
was dead and tlie niosqnito fnll of fresh blood. This blood contained abundant 
tiypanosonies, whose shape is quite different from the usual ones found in rats, 
Xagana,etc. * * * Although flagellates, coccidia-lihe bodies, etc., often were 
found fi’om time to time in the 80 mosquitoes which were dissected, this was the 
only time that trypanosomes were found. 
THE PARASITES OUTSIDE THE BODY. 
We must confirm the reports of TTasielewski and Senn, and of 
Rabinowitscli and Kempner, that if hanging drops are made of blood 
containing parasites in different stages of division a careful watching 
of the specimen will not witness the completion of the division process, 
whether the specimens be kep)t at room temperature or in the ice box 
or in the incubator. 
Jurgens found quite the contrary. He made three hanging drox>s 
of the same blood with the same XDlatinum loop. Xo. 1 was placed at 
37° C. Xo. 2 was kept at room temperature. Xo. 3 was immediately 
dried, fixed, and stained, and examination showed it to contain para- 
sites preparing to divide. On the next day Xos. 1 and 2 were dried, 
fixed, and stained. The stained specimen of Xo. 2 alwaj's showed 
the same conditions as Xo. 3; but in the stained specimen of Xo. 1 
there were rosettes and division forms, none of which was seen in 
Xo. 3. Therefore, he concludes that it is possible for certain .stages 
of the parasite under certain conditions to increase outside the body. 
It will require further investigation to determine whether the para- 
site exists in the flea’s body in the forms known to us as young forms, 
division forms, and adult loarasites, or whether there is still another 
form which has not vet been described. The fact of not beins: able 
to find in infective fleas any form resembling a trypanosome has a 
close parallel in what occurred in one of our rats. A white rat in 
whose blood we saw many parasites in agglutination for several days 
suddenly showed an absence of parasites from the blood. W e imme- 
diately performed an autopsy and made a careful search of the lungs, 
liver, spleen, kidneys, heart, brain, and bone marrow for parasites, 
but could find none. TTe were struck by the amount of granular 
debris in the liver and kidneys, but could not see any trypanosomes 
in them. 
An emulsion was made of the kidneys and injected into the perito- 
neal cawty of a young rat. The liver was treated in the same man- 
ner and injected into two young rats. On the ninth day all three 
rats had parasites in their blood and a few days later developed 
heavy infections. While some unknown form of the parasite may 
have been present, it is of course possible that well-known forms of 
the trypanosomes were in the kidneys and liver and escaped -notice. 
Jurgens produced infection with O.OOOOOo c. c. of blood. If this 
amount of blood be added to 1 or 2 c. c. of salt solution, the dilution 
of the iDarasites would be so great that they might readily be missed in 
hanging-drop preparations. 
The possibility of the existence of some very minute form of the 
