Abstract
Summary and Conclusions T. equiperdum, T. brucei and T. hippicum were cultured serially on chick embryos with ease by the methods developed. The growth of the cultures was followed by removing blood samples through cuts made in the shell and subculturing was carried out on the basis of the findings. Embryos inoculated on the twelfth to fourteenth day continued to develop and more than fifty percent hatched. The infection either persisted in the chick causing its death on the fourth to the sixth day or disappeared within forty-eight hours after hatching. It was impossible to infect three to seven day old chicks by injecting them with suspensions of trypanosomes from guinea pigs, chick embryo cultures or blood of chicks hatched with heavy infection. The morphology of the parasites in the chick embryo cultures or in the infected chicks was identical with that observed in the mammalian hosts. The cultures of the trypanosomes in chick embryos are uniform and easy to duplicate and the same is true of the infection in white rats and white mice. As a result, two new tools are readily available for the determination of the trypanocidal action of chemotherapeutic agents. In addition, the luxuriant growth of the organisms in the chick embryo could be utilized to provide enormous numbers of parasites for such purposes as vaccines should such a need arise. Attention should be directed to the fact that the data apply to only one strain of each of the three species of trypanosomes. Whether these data will be confirmed when these studies are extended to include other strains cannot be assured. However, the three strains are typical and of known origin.