512 
ZOOLOGY: R. ERDMANN 
no trace of a blepharoplast or flagellum (fig. 7, i and k), and animals with 
nucleus, blepharoplast and flagellum (fig. 7, h) . They were much smaller 
and narrower than the typical Trypanosoma brucei. The significance 
of this temporary disappearance of the nucleus is not clear. Such 
animals might be compared with von Prowazek's so-called ^ndiferrente 
Formen.' However, the two different types which arise from these 
animals are not degeneration forms because they give rise to small try- 
panosomes (fig. 7, 1) about eleven days after inoculation into the plasma. 
The appearance of the above mentioned types gives the only suggestion 
of dimorphism, which some might interpret as sexual in nature, which 
has appeared in my experiments. 
Summary. — It is believed that the method employed in these experi- 
ments — which is a modification of tissue culture methods and excludes 
the possibility of the presence of confusing flagellate organisms — affords 
the means of following, outside the body of the invertebrate host, the 
sequence of changes in the life of trypanosomes. 
Thus far its use has resulted in the discovery of dimorphic forms, 
latent or round forms, and crithidia-like forms in Trypanosoma brucei 
outside of the invertebrate host. The crithidia-like forms, when 
reinoculated into a rat, give rise to typical Trypanosoma brucei from 
which they had taken their origin. 
1 Minchin, Protozoa, London, 1912, p. 202; Minchin and Thomson, Q. J. Microsc. Sci., 
London, 60 (1915). 
2 Carini, Ann. Inst. Pasteur, Paris, 24, 149 (1910). 
3Novy and McNeal, Contrih. Med. Res., 1903; /. Inf. Dis., 1 (1904). 
4 McNeal, /. Inf. Dis., 1, 535 (1904). 
^ Laveran and Mesnil, Trypanosomes et Trypanosomiases, Paris, 1912, p. 459; Ann. Inst. 
Pasteur, 15 (1901). 
6 Moore and Breinl., Ann. Trop. Med. Parasit., 1 (1907). 
7 Moore and Breinl, Ann. Trop. Med. Parasit.,, 2 1908); Proc. R. Soc, B. 80 (1908).. 
8 Harrison, Proc. Soc. Exp. Biol. Med., 4 (1907); /. Exp. Zool., 9 (1910). Burrows, /. 
Amer. Med. Ass., 55 (1910); /. Exp. Zool., 10 (1911); Walton, Proc. R. S. B. 87, 452 (1914). 
9 Erdmann, Proc. Soc. Exp. Biol. Med., 12, 57 (1914). 
i» V. Prowazek, Centralbl. Bakt., Jena, 68 (1913). 
" Schilling, Berlin, Arb. Gesundhtsamt. 21, 188 (1904). 
12 Oehler, Zs. Hyg., Leipzig, 78, (1914) ; Heidelberg Sits Ber. Ak. Wiss., 1911. 
13 Kiihn und v. Schuckmann, Zool. Jahrb., Jena, Suppl., 1912, p. 338. 
14 Crawley, Bull. 119, Bur. An. Ind., U. S. Dept. Agric, 1909, p. 6. 
15 V. Prowazek, Berlin, Arb. Gesundhtsamt, 22 (1905). 
16 Doflein, Arch. Protistenk., 19, 222 (1910) ; Freiburg, i. B., Ber. nat.f. Ges.. 20 (1913). 
17 Bradford and Plimmer, Q. J. Microsc. Sci., 45 (1902). PI. 21, figs. 6, 7, 8, 14. 
