398 Texas-fever or Red-water in Cattle, [auc, 



which are not Red-water farms. They are, however, capable 

 of becoming Red-water farms if sick or recovered animals 

 are put to graze upon them, and it has already been mentioned 

 that the blood of recovered animals may retain its virulence 

 and therefore be capable of infecting ticks for a considerable 

 time (several months, and, in the case of tropical piroplas- 

 mosis, several years). 



A few experiments have been made for the purpose of dis- 

 covering whether British ticks are capable of carrying the 

 tropical and more fatal form of Red-water, and this was 

 found to be the case, though the experiments are not yet con- 

 cluded. 



Seasonal Appearance of Red-water. — In this country Red- 

 water is most prevalent from March to June and during 

 October and November, and these periods of the year corre- 

 spond with the time of the greatest prevalence of ticks, parti- 

 cularly the adult forms, according to field and laboratory 

 observations. Outside these periods odd cases of the disease 

 are met with, the reason being that although the periods 

 mentioned are those at which the dangerous stages of the tick 

 are most prevalent, they do not all accomplish the moult at 

 the same time; some are earlier and some are later. 



Prevention of Red-water. — -As the result of all these investi- 

 gations, a certain amount of advice under the head of preven- 

 tion may be given as regards English Red-water. 



The owner of a Red-water farm may attempt to reduce his 

 losses, or even to eradicate the disease, in one of three ways : 

 — (i) He may resort to inoculation, and for this purpose the 

 blood of an animal about a month recovered from the disease 

 should be used. If susceptible animals are inoculated with 

 an appropriate dose of infective blood, they develop an attack 

 of the disease of varying intensity, and after recovery they 

 exhibit a high degree of resistance to natural infection. The 

 inoculated animals should be kept indoors during the process 

 of immunisation (for about a fortnight to three weeks), so that 

 they can be attended to in the event of a severe attack being 

 induced. Under such circumstances accidents should be very 

 infrequent. 



Animals bred and reared on Red-water farms are usually 

 highly immune, owing to an attack of the disease contracted 



