10 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



salivary glands, how is not known. I should add that the 

 mode of development is different in the case of other trypano- 

 somes. 



A further point for consideration arises. In the case 

 of malaria the disease is purely a man to man infection, and 

 we have the important factor that the native children, who 

 for the most part appear to be in abundant good health, 

 have numerous parasites in their blood, they constitute in 

 fact the reservoir from which, for example, the European gets 

 infected. It is a man to man disease. In sleeping sickness this is 

 not so, The natives do not here constitute a permanent reservoir, 

 for the simple reason that they all die. How then does 

 infection spread ? The answer is that the same trypanosome, 

 at least this appears to be proved in the case of T. rhodesiense, 

 occurs in native game. The game enjoys an immunity to 

 the disease. The game infects the fly and so the disease 

 is transmitted to man. The game constitutes the reservoir. 

 What should be done in Africa to limit this spread of the 

 disease by the game is a question into which a special 

 Commission enquired this year. It is proposed to try an 

 experiment to see what will be the result of exterminating 

 or reducing the quantity of the game from a small defined 

 area. It is practically impossible to attack the fly. 



T. tullochi and T. grayi. It may be further noted that 

 tsetse flies contain in nature these trypanosomes in their 

 gut. So far inoculation of these into animals has produced 

 negative results, but it would appear as if they deserved 

 re-study. 



Xala-azar. 



Is an extremely fatal disease prevalent in India, Sudan, 

 parts of China, and elsewhere. The parasites that cause 

 this disease exist in large numbers in endothelial cells in the 

 spleen, liver, bone marrow, etc. A disease indistinguishable 





