58 SUMMARY OF CURRENT RESEARCHES RELATING TO 



be developed from a pair of arrested mitotic figures developed out of the 

 distal of the two segments into which the original kinetonucleus divides. 

 The process of division is described. 



Trypanosomes of Frog and Leech.* — Carlos France finds that the 

 Invertebrate host of Trypanosoma costatum and T. roiatorium of the frog 

 is a leech. From the leech he has been able to infect the frog. There 

 is a Trypanosome phase in the frog, and a Herpetomonad phase in the 

 leech. The author has also some notes on the culture of the frog's 

 trypanosomes | and on their intra-vitam staining. $ 



Development of Piroplasma canis in Dog.§ — G. H. F. Nuttall and 

 G. S. Graham Smith describe the appearance of this parasite in unstained 

 preparations, its mode of multiplication, including an account of the 

 nuclear changes, the fate of the various forms as observed in the living 

 blood, and the complete cycle of development within the blood. The 

 mode of multiplication stated briefly is as follows. A free pyriform 

 parasite enters a normal red-blood corpuscle and rapidly assumes a rounded 

 form. It then enlarges and passes through an actively amoeboid stage, 

 at the end of which it again becomes rounded. After a short period of 

 quiescence in this condition, it protrudes two symmetrical processes, 

 which rapidly grow and become pear-shaped. The protoplasm of the 

 parasite flows into these processes, and its body consequently gradually 

 diminishes, until it is represented by a minute rounded mass, to which 

 the pyriform processes are attached. Eventually this also disappears, 

 and, finally, two mature pyriform parasites are left, which are joined 

 together for a time by a thin strand of protoplasm. After a variable 

 time these parasites are liberated by the rupture of the corpuscle, and 

 swim away, to enter fresh corpuscles and repeat the process. Occasionally 

 a single rounded intra-corpuscular parasite gives rise to four or more 

 pyriform parasites by the protrusion of a corresponding number of 

 processes. The authors never observed any forms which could be re- 

 garded as gametes. 



* Bull. Soc. Portugaise Sci. Nat., i. (1907) pp. 27-8 (2 figs.). 

 t Tom. cit., pp. 5-8 (3 figs.). % Tom. cit., pp. 9-11. 



§ Journ. Hygiene, vii. (1907) pp. 232-72 (3 pis. and 14 figs.). 



