Nearly ail the trypanosomes contain basophilie granulations, 
scattered throughout the cytoplasm or arranged in lines both in 
the anterior and posterior halves. The granules are coarse, about 
T U in size, and as many as i6 to iS may be seen at times. The 
latéral margins of the trypanosome are usually more deeply stai- 
ned than the middle portion. The longer forms hâve a longer 
flagellum and contain fewer granules. 
The tr^’panosome T. hippicum nv. sp. seems to resemble T. 
dimorphon more closely than any other one. Dr. Laveran, who 
very kindly looked over my préparations is of the opinion that 
the trypanosome is apparently a new species and is different from 
T. equinum and T. equiperdum. 
At this writing the following animais hâve been infected ex- 
perimentally : 
Dog 
native 
Hog 
native 
Goat 
native 
Cat 
native 
Kitten 
native 
died 
Guinea pig 
native 
died 
Monkey Cebiis 
Rabbits 
native 
died 
Agouti 
native 
[Dasyprocta agouti) 
Rats M. rattus 
native 
Rats M. norvégiens. 
albino 
died 
Alice M. mnscnlus 
native 
died 
A calf from the hospital herd, Jersey grade, lias resisted infec¬ 
tion. 
So far as I can learn at présent this trvpanosomal disease had 
not been observed in the Canal Zone since the American occupa¬ 
tion in 1904. There hâve been a few vague accounts of losses 
among native stock last vear, 1909, during the rainv season. 
Columbians speak of a disease met with among native horses 
frorn the interior called Derrengadera and it mav be that the 
disease outlined above is Derrengadera, our mules and horses be- 
coming infected while in the Gatun pasture in contact with native 
horses, although there hâve been no cases of this disease appear- 
ing among nati\m horses at Gatun. The blood of several native 
horses upon examination lias been négative for trypanosomes. 
It is interesting to note that the disease appeared here among 
animais recentlv arrived from the United vStates. Tt was called 
(( Swamp Fever » (the infections anaemia of equines) by the lo- 
