Protozoan Cattle Fever. Texas Fever. Paludism of Cattle. 591 



lyignieres claims to have followed all these changes in the blood 

 "kept in a sterilized glass cup at room temperature or in the ther- 

 mostat, and in the stomach of the tick, as well as on the warm 

 -Stage of the microscope. 



He claims to have made a further success in cultivating the 

 parasite in ox-blood serum highly charged with haemoglobin. It 

 was only occasionally, and by the use of blood extraordinarily rich 

 in the parasites, that success was obtained. In one such case he 

 produced five successive cultures, the product being the rounded 

 forms only and within these the germs. There were no piriform 

 bodies. These are not formed outside of the red globules. The 

 third successive culture in this medium grew with great readi- 

 ness, producing larger parasites with less disposition to contract, 

 but the fourth and fifth cultures were encreasingly poor. Inocu- 

 lation with these cultures failed to produce the disease. To ex- 

 plain this the doctrine of passive germs, strong for survival, but 

 w^eak pathogenically, is hazarded. 



To summarize, the successive stages of the piroplasma are : 

 ist. The intraglobular pear-shaped bodies with flagellum often 

 connecting two bodies. 2nd. The rounded bodies with refrangent 

 nucleus — intraglobular or extraglobular. 3d. The free round 

 bodies with the nucleus divided into 2 to 5 chromatin masses. 4th. 

 The free chromatin masses, large, active, infecting germs, and 

 small, passive, non-infecting germs. The insuccess of inocula- 

 tions of cattle with the last named bodies throws an air of doubt 

 upon them as links in the pathogenic chain. Definite informa- 

 tion on the antecedents, environment, food, etc., of the cattle un- 

 successfully inoculated, including the season, shelter and meteor- 

 . ological conditions might have brought us a step nearer to the 

 full life history of the piroplasma. 



The Cattle Tick : Boophilus Annulatus : Boophilus Bovis : 

 Ixodus Bovis : I. Dugesii : The Invertebrate Host of the Texas 

 Fever Organism. As early as 1868 shrewd observers had noticed 

 that in all outbreaks of Texas fever the affected animals were 

 covered with ticks, and drew the natural inference that the dis- 

 ease was due to the bites of these insects. But the prevalence of 

 ticks in localities where the disease was unknown served to draw 

 attention away from the important fact that was suggestive of 

 the true explanation of the disease. The truth, however, con- 



