594 Veterinary Medicine. 



the stock yards during the dry, hot, midsummer weather died of 

 Texas fever within a month, while those that passed through 

 the same yards during a particular rainy week, all escaped. 

 Berkau has shown that, in the absence of the coating of the 

 glutinous saliva, the eggs do not hatch, and here we may assume 

 that this covering was washed off by the rains and the eggs 

 perished. 



15. It has long been noticed that the ticks are scarcely at all 

 dangerous to young calves living on milk. This applies not only 

 to calves born of cows native to infected localities, and therefore 

 possibly having a congenital immunity, but also to the calves 

 of northern and susceptible cows, and which were exposed 

 simultaneously with their dams. It suggests a special defensive 

 power in even the bovine system when sustained on animal food. 

 In the Bureau of Animal Industry experiments, calves of four 

 months, already using vegetable food freely sickened, but still 

 as a rule, recovered. 



16. The Bureau fed three cattle with adult live ticks (2000 to 

 an animal) but no infection resulted. 



17. Four cattle were injected intravenously with the liquid 

 charged by crushing ticks in a mortar with distilled water. In 

 some cases the liquid was put through a Pasteur filter, in others 

 only through two thicknesses of filter paper. No infection 

 ensued. 



18. Lignieres injected, subcutem, in different animals the pulp 

 of the ticks at all stages of life, ground in a mortar with distilled 

 water, but found in no case tristeza as the result nor any destruc- 

 tion of red globules. 



The apparent paradox involved in the last three items probably 

 finds its explanation in the statement of NicoUe and Adil-Bey 

 that, in biting, the tick instils into the wound a venomous saliva 

 which causes local congestion and infiltration and presumably 

 operates on the blood globules as well. Curtice describes the two 

 racemose glands situated under the head shield, the secretions of 

 which are pressed out by the movements of the mouth ring and 

 appendages. How much of this irritant and toxic action is in- 

 herent in the saliva, and how much due to the protozoan con- 

 tained in it has not been shown. NicoUe, Adil-Bey and, later, 

 Lignieres showed a similar toxic property in the blood. Three 



