548 Veterinary Medicine. 



To summarize, the successive stages of the piroplasma are : 

 ist. The intraglobular pear-shaped bodies, with flagellum often 

 cotinecting 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 Bovis : Ixodes 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 disease was due to the bites of these in- 

 sects. But the prevalence of ticks in localities where the disease 

 was unknown served to draw attention awa}' from the important 

 fact that was suggestive of the true explanation of the disease. 

 The truth, however, constantly obtruded itself that casual cases 

 were never found in the absence of the tick. Finally, in 1889, 

 Kilborne conceived the idea of putting the matter to the test, and 

 with the approval of the Chief of the Bureau of Animal Industry, 

 set aside special paddocks for this purpose. * Five native cattle 

 were placed, at midsummer, with three South Carolina cattle, 

 from which all ticks had been carefully picked, and they com- 

 pletely escaped infection. 



After seventy-one days, on September 6th, when the hottest 

 weather had passed, two were turned into a lot with four South 

 Carolina cattle of the original herd which had stocked the pasture 

 with ticks. Of the two one died of Texas fever, September 20th, 

 and the other sickened in the last week of September, and had a 

 relapse in October, but finally recovered. Of eleven other native 

 cattle placed in this tick-infe.sted field up to September 30th, ten 

 sickened and one escaped. One animal placed in the field Octo- 

 ber 19th escaped. 



Again three North Carolina cattle and three natives were placed 



