280 THE SHEEP OF GREAT BRITAIN. 



properly with heavy Longwools requires time and strength. 

 Each sheep will take from three to five minutes ; but it is well 

 spent, as the result is thoroughly clean wool. At intervals, 

 depending upon the condition of the animals, the bath must be 

 emptied, and fresh water admitted. It is at this point that the 

 water should be utilised if practicable for irrigation. The 

 sheep being constantly in hand, there is no fear of exhaustion ; 

 when finished, it should have one good plunge, and be allowed 

 to swim out at the lower side of the bath, which should be 

 shelved so as to assist egress. 



The comfort to the animals from a clean skin is evidenced by 

 their basking at full length in the sun, where they will remain 

 for hours ; and this brings us to another important considera- 

 tion, viz., the value of sheep dipping, both as affecting health, 

 removing vermin, and favouring wool growth. In order to 

 understand this question it will be necessary, very briefly, to 

 consider the principal external parasites to which the sheep is 

 liable. Our remarks must necessarily be limited; those who 

 wish to pursue the subject will find an exhaustive essay, by the 

 late principal of the Royal Veterinary College, Mr. James 

 Simonds, in the first volume of the "Eoyal Agricultural 

 Society's Journal," new series, 1865. 



The principal enemies of the sheep are the so-called tick 

 {Melojphagus ovinus) ; the louse of the sheep (Trichodiatis ovis) ; 

 the origin of the hateful disease known as " scab," which is 

 caused by a species of Acarus; and last, but not least, the 

 maggot of the flesh fly, which frequently causes intense irrita- 

 tion in hot weather. 



The tick is found, more or less, in all sheep, and if unchecked 

 is sure to increase, though procreation is not so rapid as in 

 many other insects. It appears first in the pupa state, in which 

 condition it is expelled from the parent, and adheres to the skin 

 of the sheep. How long the pupa is being formed has not been 

 ascertained, but Professor Simonds believes that the after stages 

 occupy about fourteen days ; warmth and a certain amount of 

 moisture are necessary, both being supplied by the skin. During 

 winter the skin is tolerably free, but as warm weather approaches 

 the parasites abound, and must be destroyed, otherwise they 

 cause such irritation that the animal's health suffers. 



