The schizogony in the life-cycle of Sarcocystis muris

Abstract

The first period of the life cycle of Sarcocystis muris extends from the date of infection to the entrance of the unicellular parasite into the muscular tissue of the host (20 to 30 days). 1 In my former publications I could only describe from this period some large ameboid forms found in the walls of the intestine and in the lymph vessels of experimentally infected mice. 2

My present investigation shows the appearance of small ameboid and schizogony forms six days after infection. These stages were discovered after feeding sarcosporidia to young mice nourished with milk from birth to the end of the experiments. These small schizogony forms (0.3 to 0.4 μ) consist of a tiny protoplasmic body with a caryosome-nucleus, and arise from smaller ameboid organisms which show typical schizogony.

Although these mice did not contain any other protozoan parasites in the intestine, I hesitate to connect positively the small ameboid and schizogony forms with the newly introduced Sarcosporidian “spore” until further study actually demonstrates the transition.

A complete account of the work will appear in the Arch. d. 2001. expér. et gén., T. 52, 1914.