ANIMALS SUSCEPTIBLE 585 



life cycle of the piroplasma, not as degenerative basophilic granules 

 of the protoplasm of the red blood corpuscles. 



Kossel and Weber studied the hemoglobinuria of cattle in Finland 

 and confirmed the previous observations of Smith and Kilbourne, 

 and were able, by the use of the Romanowski stain, to add further 

 morphologic details. They found that the very smallest intra- 

 corpuscular parasites, which have about one-sixth of the diameter of 

 the red blood corpuscles, are very delicate ring bodies, the margin 

 of which stains red, the inner portions blue. Other small parasites 

 are irregular in shape and show the beginning of an arrangement 

 of the chromatic substance into two portions. In somewhat larger 

 bodies the division of the chromatin into two parts has become quite 

 distinct, while sometimes the chromatin is split up into four portions. 

 These authors, however, were not able to demonstrate in piroplasma, 

 asexually or sexually, dividing bodies as they occur in human and 

 avian malarial parasites which form spores by two distinct types. 



While nothing definite is known as to the propagation of the piro- 

 plasma in the body of infected cattle it is quite evident that it must 

 take place in some way, since an enormous increase in the number of 

 parasites within a short time can be observed in certain stages of the 

 disease. Doflein has observed that the nucleus-like body in the 

 interior of the parasites under some conditions breaks up into three, 

 four, or more smaller fragments. He looks upon this process as an 

 asexual spore-formation (schizogony), and he considers the large pear- 

 shaped bodies as sexual forms (gametocytes). 



Whether the piroplasmata found in animals of the cattle tribe in 

 various parts of the world are one identical species, or whether they 

 are varieties or distinctly different species, is a question which cannot 

 as yet be decided definitely. In East Africa, Robert Koch found 

 bacilli-like forms, often four in one corpuscle, in a very large percentage 

 of the red blood corpuscles in the fatal hemoglobinuria of cattle. 

 These rods by curving upon themselves formed ring-like bodies; 

 they were generally thicker in the middle than at either end, and by 

 intermediate forms gradually lead to the typical shape of the piro- 

 plasma. Since such forms have never been seen in Texas fever in the 

 United States, this East African piroplasmosis is perhaps due to a 

 species different from Piroplasma bigeminum. 



Animals Susceptible. The piroplasmosis of cattle in America is 

 not transmissible to other animals. Experiments have been made 

 upon horses, asses, sheep, rabbits, guinea-pigs, dogs, cats, pigs, mice, 

 rats, and chickens. The tests were all negative. If, however, blood 

 from an animal sick with Texas fever is inoculated by any one of a 

 variety of methods, such as intravenous, subcutaneous, intraperitoneal, 

 intramuscular, intracerebral, into a healthy head of cattle a marked 

 elevation of the temperature takes place, after three to seven days, 

 and piroplasmata may be seen in the circulating blood. After a 

 few more days the number of red blood corpuscles and the hemoglobin 



