392 



TR YPA NOSOMIDM 



or general oedema, and disease of the nervous system. Secondary 

 bacterial affections are also common. The mortality is often high. 



MoRDiD An ATOMY — The lesions are often insignificant, but in- 

 flammation and enlargement of the lymphatic glands is character- 

 istic, and dropsy and inflammation of the meninges are also found, 

 which in human trypanosomiasis takes the form of meningo- 

 encephalitis, as will be described later. 



Inoculations.^ — The parasites can be spread from one animal 

 and from one species to another by inoculation of infected blood. 



Agglutinins.^ — While in the body of the host agglutinins are 

 formed, for if blood containing trypanosomes is treated with the 

 serum of an animal which has had one or more injections of blood 

 containing the same parasite, a rapid massing of the parasites into 

 rosettes, with the anterior ends pointing inwards and the flagella 

 outwards, takes place. 



This is called agglomeration, and may last a few minutes, the 

 parasites being unafiected, or may persist till they die. 



Reducing Power. — Trypanosomes have been shown by Nauss 

 and Yorke to have a marked reducing power on haemoglobin. 



Precipitins. — Mayer has shown that the serum of a dog infected 

 by T. brucei is precipitated by a salt extract of the same parasite, 

 but not by that of T. equinum, thus proving the presence of specific 

 precipitins. 



Immunity . — Active immunity, due to the action of the leucocytes 

 (Laveran and Mesnil) or to cytolysins (McNeal), can be produced 

 in certain cases, but it is not carried from mother to young. Leger 

 and Ringenbach have shown that the serum of animals affected with 

 nagana and surra, also T. equinum, T. castellanii, and T. congolense, 

 is trypanolytic for homologous and allied trypanosomes, but not for 

 others. 



Chalmers and O'Farrell have shown that T. castellanii can be 

 separated from T. rhodesiense by immune serum reactions in vitro 

 and in vivo. 



Involution Forms. — Degenerated, vacuolated involution forms 

 may be seen as a result of immunity coming on or of treatment by 

 drugs. Advanced forms after treatment with immune serum have 

 been noted by Chalmers and O'Farrell. 



Toxins. — Uhlenhuth, Hxibener, and Worthe have demonstrated 

 the presence of endotoxins in T. equiperdum, which observation 

 supports McNeal's suggestion as to their presence, and also the 

 work of Martin, Darre, and Leber. Free toxins do not exist, but 

 endotoxins can be set free by trypanolysis. 



Local Reservoirs.- — The long-continued infectivity of Glossina 

 palpalis after the removal of man from a district points to either 

 long duration of infectivity in the fly or to a local reservoir, which 

 may perhaps be found in antelopes, and perhaps other animals in 

 the case of T. castellani. 



Cultivation. — McNeal and Novy cultivated T. lewisi in the water 

 of condensation of blood-agar tubes in 1903, and obtained, at 37° C. 



