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Experiments were carried out with birds experimentally infected with Eimeria acervulina. It was found that this causative agent was responsible for catarrhal to hemorrhagic enteritis, however, the feces did not contain blood despite their becoming watery. In the duodenum it was shown to accomplish schizogony three times: the first schizogony took place up to the 72nd hour, the second one--up to the 120th hour, and the third one--up to the 168 th hour. On the other hand, gametogony started at the 168 th hr. Most severe lesions in the mucosa were found on the 7th-8th day following infection. They coincided in time with the third generation of schizonts and the gametogony. The alteration processes in the mucous membrane affected the villi to a larger extent than the propria mucosae. Villi regeneration proceeded from the 9 th to the 12 th day. The prepatent period lasted 144 hours. Macrophages were not found to carry the sporozoites to the glands. Dystrophic and necrobiotic changes in the viscera predominated over the proliferation processes, and this made it reasonable to believe that the basic moment in the pathogenesis of the disease was the mechanical destruction of the epithelial cells of the villi as well as the adsorption of toxic products from the decomposition of the necrotic cell mass in the intestinal lumen. Eimeria acervulina was said to produce pathogenic, but not lethal effects.

Studied were the morphologic changes in an experimental Eimeria adenoeides infection in turkey-poults. The birds were killed daily from the 1st to the 10th day of infection, keeping records of the gross lesions and the microscopic changes in the internal organs. It was found that Eimeria adenoeides performs two cycles of shisogony in the caeca. Most severe were the changes on the 4th and 5th day of infection, which corresponded to the second shisogony and the gametogonia. At the same time there were in the liver, kidneys, and heart granular protein dystrophy which was believed to be a second one, being the result or resorption of toxic cell detritus products in the intestines.

The dynamic of the morphologic changes taking place in the viscera of lambs was followed up in lambs with an experimental Cysticercus ovis infection. The tests were carried out with 6 two-month-old lambs infected with 30,000 ova of Taenia ovis each. The animals were killed on the 2nd, 4th, 12th, 54th, and 70th day of infection, taking notes on the gross and microscopic changes in the internal organs. It was found that in the predilection sites of localization the migrating oncospheres were transformed into cysticerci around which specific granuloma were formed from the center to the periphery, consisting of eosinophile leukocytes, epitheloid and gigantic cells, lymphocytes, lymphoid cells, and outermost--a connective tissue capsule. As the result of the abundant leukocyte infiltration the cysticerci quickly perished and a suppurant was formed instead that later on was replaced by connective tissue.

Comparative studies were carried out on the inhibitory effect of some oleoemulsions on the acute course of an experimental coccidial infection caused by Eimeria tenella. Such effect was demonstrated with the oral application of sporulated oocysts both with the complete and incomplete Freund's adjuvant and with oleum ricini and oleum helianthi in combination. The results of histopathologic investigations showed that the two types of Freund's adjuvant inhibited the rapid and joint excysting of a large number of oocysts. Inhibited was the invasion of sporozoits in the epithelial cells of the mucous membrane and thus the acute course of the coccidial infection caused by Eimeria tenella.

Studies were carried out on the action of sulfachlorpyrisine-Na (ESB3) on the endogenic development of Eimeria tenella in the case of experimental infection in birds. Most sensitive to the preparation were the endogenic forms between the 48 h and the 72 nd following the act of infection. Given to birds on the day of infection and 24 hours later it produced no harmful effect on the further endogenic development of E. tenella. When the preparation was applied at the 72 nd hour it led to the degeneration of most of the II generation schizonts and inhibited their further development. As a result no oocysts were found in the feces of birds up to the 10 th-11 th day after infection. When applied at the 92 nd and the 120 th hour sulfachlorpyrisine-Na interfered with the development of the already finite forms of gametogony without concurrent degenerative effects.