TRYPANOSOMIASES OF RHODESIA. 14! 



" From the new blcpharoplast produced by divisic n a new flagellum 

 grows out either close beside the old one or at some distance from 

 it. The body of the trypanosome widens, and after the production of 

 two kineto-nuclei, two tropho-nuclei, two blepharoplasts and two Hagellas, 

 begins to divide from the anterior end backwards-'" * 



As to schizogony or sp'ofogeny of the pafasite, tlie greatest 

 confusion exists. Aloore and Breinl described certain " latent 

 bodies " which Fanthan has recently described as non-flagellate 

 stages found especially in the lungs, spleen and bone-marrow, 

 during periods of decrease of trypanosomes in the peripheral 

 iblood of the host. The non-dagellate body contains the nucleus 

 and kineto-nucleus, the cytoplasm and flagellum having disin- 

 tegrated, and is supposed to have a definite capsule which renders 

 it resistant. Under certain conditions, it is claimed they can 

 be seen to gTow and flagellate, turning into trypanosomes. 



JUit none of the present theories appear to be completelv 

 satisfactory. It is known that during the course of an infection 

 the peripheral blood contains from day to day varying numbers 

 of parasites, increasing or disappearing in definite cycles. 



It is generally assumed that during those periods when para- 

 sites are absent, or rather are not visible in the peripheral blood 

 when examined under the microscope, that the latent or resistant 

 stage occurs in some of the organs (spleen, bone-marrow, lungs). 

 Nevertheless, such apparently sterile blood is infective by inocu- 

 lation into susceptible animals. Bruce has conducted filtration 

 experiments and has found the filtrate non-infective, arguing 

 therefrom against an ultravisible stage of tlie organism. Filtra- 

 tion experiments, however, are liable to many fallacies. The 

 viscidity of the material plays an important part in its passage 

 through the porcelain. If, therefore, a minute form of the 

 organism were embedded in a protoplasmic matrix, it is con- 

 ceivable that it might fail to make its Avay through the filter. 

 One of the features of trypanosomiasis is a curious alteration in 

 the blood known as agglutination : this or some similar change 

 would perhaps interfere with filtration results. 



An interesting phenomenon is met with after the application 

 of certain therapeutic agents, many of which cause the rapid 

 disappearance of the organism from the peripheral blood, -whicli, 

 however, reappears after a certai4i period. Subsecjuent exhibi- 

 tions of the drug fail to produce the same result — the parasite 

 having acc[uired a tolerance or immunity to the agent. The 

 phenomenon has given rise to the system of applying a second 

 drug having no chemical relation to the first. A drug, to be 

 successful in sterilising the host of the parasite, must be ]iara- 

 sitropic but not organotropic. Many drugs or combinations of 

 drugs have been claimed to possess these desired properties, Intt 

 unfortunately, in spite of the optimism of the lay press, it must 

 be admitted that a specific has not yet been found. Alany agents, 

 while successful or nearly successful in eradicating the parasite, 



* Tobev. 



