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of oil and sulphur ; Gordon's method of rubbing with petroleum. 

 These three methods are all open to the same objection in that they 

 are expensive and hardly capable of apphcation to a large number of 

 animals. 



The burning of herbage is regarded by some as a certain remedy 

 and there is no doubt that enormous numbers may be destroyed in this 

 way, but the author thinks that the value of the remedy has been 

 exaggerated. Bush fires at the end of the hot season will kill all the 

 young larvae attached to the herbage, but numbers of females have 

 fallen to the ground and their eggs, as well as the ticks which are attached 

 to the cattle, escape and the eggs hatch more rapidly, as the cover having 

 been destroyed, they are exposed directly to the sun's rays. Firing 

 the herbage undoubtedly diminishes the number of ticks, but in order to 

 obtain satisfactory results, it is necessary to carry out the operation as 

 late as possible, and this question is the subject of much discussion in 

 South Africa. 



The most practical and most extensively employed method is 

 dipping ; the author gives the following formulae for dips. Three day 

 dip: Arsenite of soda 41b., soft soap 3 lb., petroleum 1 gallon, 

 water 400 gallons. Five day dip : Arsenite of soda 8 lb., soft soap 

 5| lb., petroleum 2 gallons, water 400 gallons. 



The author then discusses the action of arsenical dips upon ticks 

 and says that the ticks are killed by the direct action of the arsenite. 

 In the numerous experiments which have been made, it has been proved 

 that, after the use of a dip with arsenite of soda as a base, the number 

 of female ticks which gorge themselves diminishes considerably, 

 the young females dying before reaching this stage. The already 

 gorged females are killed, or if they survive and lay eggs, these 

 are few in number and many do not hatch, the larvae resulting from 

 the remainder being feeble and hardly able to escape from the egg. 

 The author says that as M. anmdatus var. decoloratus requires 3 or 4 

 weeks to complete its metamorphosis, one dipping every 3 weeks is 

 sufficient, but seeing that the young larva may live for 6 months and 

 the adult nearly a year before attaching themselves to a host, the dip 

 must be kept up for at least this period. 



In the case of R. evertsi dipping is necessary at least every 8 days 

 and must be continued for at least a year. R. appendiculatus, the 

 chief carrier of East Coast fever, requires 3 hosts and dipping every 

 3 days is required in order to catch the tick in all stages of its 

 existence, and this must be continued for at least 14 months. For 

 A. hebraeum, dipping every 4 days, for 7 months at least, is 

 required. It is thus obvious that before deciding on the frequency 

 of dipping, the tick to be destroyed must be determined. It has 

 been shown that animals can stand dipping every 5 days, but as 

 a matter of practice they are dipped every 8th day and the treatment 

 completed by hand. If an epidemic of East Coast fever should break 

 out, it is absolutely necessary to dip the cattle every 3 days. 



In conclusion the author reviews an objection which has been raised 

 against dipping, since if it be regularly practised, large numbers of non- 

 immune animals will be produced and these if transferred to a tick 

 infested district, may acquire the diseases in an exceedingly virulent 

 form. The author thinks that this objection, which at first sight is 

 ver}' serious, mav be easily refuted, because the movements of cattle 



