127 



There is a great morphological difference between some 

 genera, no difference at all between others, and the same as 

 to their biological characters, but all are obligate parasites or 

 commensals in the body fîuids of the higher animals and trans- 

 ported from one host inanother by bloodsucking insects. 



On examining the Leiden rats, I found trypanosoma lewisi 

 in nearly every middle-aged specimen of decumanus that came 

 to hand, just the same at Balik-Papan (Borneo,) in marked 



door. 



y 



stick, can be taken out- 

 Cage of ' ■ / 



\>ji///ii/i>nu///w^fw/Af^Mj'M'fJM/x^7n!mi 



wire netting 



/ 



/clay pipe. 



'wooden sucker covered with tin-plate 



Fig. I. Cage for Mus Decumanus 



contrast with my experience at Pladjoe (Sumatra) were I never 

 saw Trypanosoma in rats, neither in Mus Decumanus, nor 

 in Mus Rattus. 



I did not use the Leiden trypanosomes for my experiments, 

 the rats being wild and said to die soon in captivity, though 

 I must mention the fact that I kept many of them alive for at 

 least one year in a cage that allows them to live in the dark 

 and undisturbed, (fig i). 



They are however difficult to handle and narcotics are inevitable. 



Professor Dr. D. A. DE JONG possessed two strains of try- 

 panosomes, received some four years ago from the Pasteur 

 Instute at Paris, by the kindness of Professor Mesnil. They 

 were since kept in guinea-pigs. When arriving, the first strain 

 tryp. brucei (ngana) killed a mouse in four days, the second, 

 tryp. equiperdum (dourine) in about six weeks. 



As you know the trypanosoma brucei is the parasite that 

 causes the disease called in Central Africa »Ngana« that made 

 Livingstone loose so many of his draught-beasts. Another name 

 for it is tsè-tsè-disease, the virus being transmitted by the 

 tsè-tsè flies, (glossina morsitans). 



Dourine, caused by trypanosoma equiperdum, befalls chiefly 

 horses and takes a far more chronical course than ngana. As 

 nowadays both our strains kill mice in about four days I doubt 

 wether really the dourine strain is still in our possession. 



