1909.] Texas -fever or Red-water in Cattle. 



399 



in the early stages of their life. Young animals suffer much 

 less acutely than older animals from an attack, and one must 

 be very careful indeed in inoculating bovines above eighteen 

 months of age. 



It will seldom be necessary to inoculate animals reared on 

 the infected farms, and the operation will be almost entirely 

 confined to those bought in from non-Red-water districts or 

 farms. One great objection to the inoculation method is that 

 the inoculated animals are capable of keeping up the infec- 

 tion in the ticks on the pastures, but there are certain pastures, 

 the nature of which makes it practically impossible to combat 

 the disease by any other method. 



(2) If the farm is heavily infested with ticks, which is some- 

 what rare in this country, an attempt may be made to reduce 

 their numbers by dipping the animals while the parasites are 

 attached to them. For this purpose it is best to put a large 

 number of sheep on the pastures as tick collectors. There 

 are, however, various objections to the dipping method. In 

 order to catch the greatest number of ticks, the animals have 

 to be dipped more frequently than is convenient or safe (once 

 every ten days). 



Close observation shows that none of the dipping materials 

 commonly used have a particularly destructive effect on ticks, 

 nor can they be relied upon to keep ticks off the animal for 

 any appreciable time. It might be mentioned here that dips 

 for the destruction of ticks have acquired a reputation quite 

 in excess of their value owing to the fact that the British 

 ticks, in order to complete their development, naturally drop 

 off their host in a few days, and the dip often gets the credit 

 of having destroyed them, or of having made them let go their 

 hold. If engorged female ticks be collected from animals 

 which have been dipped, it will be found that a large number 

 of them remain alive for a long time, and lay their eggs in 

 spite of the dipping. 



Mr. Stockman is of opinion, however, that continued 

 dipping, even though it be unlikely to bring about the eradica- 

 tion of ticks, must be held to reduce their numbers, especially 

 if one dips frequently and chooses for the dipping periods 

 the seasons March-June and October-November, when the 

 impregnated adults are most prevalent. The best results,. 



