478 Trypanosoma leivisi 
and by Moore, Breiul and Hindle pi’oves only the existence of chromidia ; 
neither are Schilling’s recent proofs suggestive. 
Under abnormal conditions hypertrophy takes place affecting the 
nucleus and the blepharoplast, with subsequent formation of chromidia 
and final fragmentation. Similar stages found in the rat-louse have been 
described as sexual cells. 
Considei'ing these results in connection with previous observations of 
Stiickland and myself, we may conclude that as yet nothing whatever 
indicates the occurrence of any sexual process in the life-cycle of T. 
lewisi, both in the vertebrate and invertebrate hosts. 
REFERENCES. 
Giemsa (1910). Ziu’ Farbung der Feuchtpraparaten und Schnitten mit der 
Azureosinmethode. Centralhl. f. Baht. Abt. 1, Oi’ig. Vol. Liv. p. 489. 
Hindle (1909). The life-history of Trypanosoma dimorphon. Univ. of California 
Public, in Zool. Vol. vi. p. 127. 
Laveran and Mesnil (1901). Eecherches morphologiques et experimentales sur le 
trypanosome des rats. Ann. Pasteur, Vol. xv. p. 673. 
Minchin (1909). The structure of T. leivisi in relation to microscopical technique. 
Quart. Journ. of Microsc. Sci. Vol. Liii. p. 755. 
Moore, Breinl and Hindle (1908). The life-history of Trypanosoma lewisi. Ann. 
Tropic. Med. and Parasitology, Vol. ii. p. 197. 
Prowazek (1905). Studien liber Saugetiertrypauosomen. Arb. Kaiserl. Gesundh.- 
Amte, Vol. xxii. p. 351. 
- (1909). Physiologic der Einzelligen, Leipzig (Teubner). 
Rabinowitsch and Kempner (1899). Uber Blutparasiten speziell iiber Rattentry- 
panosomen. Zeitschr.f. Hyg. Bd. xxx. p. 251. 
Rosenbdsch (1909). Trypanosomenstudien. Arch. f. Protistenhunde, Vol. xv. p. 
263. 
ScHAUDiNN (1904). Generations- und Wirtswechsel bei Tryiianosoma und Spiro- 
chaete. Arb. Kaiserl. Gesundh.-Amte, Bd. xx. p. 387. 
Schilling (1910). Das Vorkommen von Autogamie bei Trypanosoma lewisi. Arch, 
f. Protistenhunde, Bd. xix. p. 119. 
SwELLENGREBEL (1910). Fixation and Staining of Trypanosoma lewisi. Parasitology, 
Vol. III. p. 226. 
SwELLENGREBEL and Strickland (1910). The development of T. lewisi outside the 
vertebrate host. Parasitology, Vol. in. p. 360. 
Swingle (1907). Some studies on Trypanosoma lewisi. Trans. American Microsc. 
Soc. Vol. xxvii. p. 111. 
Wasielewski and Senn (1900). Beitrage zur Kenntnis der Flagellaten des Ratten- 
blutes. Zeitschr.f. Hyg. Bd. xxxiii. p. 246. 
