The Sheep-Scab. 29 



lie in a state of incubation beneath the surface 

 of the skin; the shells being impervious to the 

 effects of the decoction. There is no prepara- 

 tion strong enough to destroy the eggs, which 

 does not, at the same time, endanger the life of 

 the sheep. In the course of from one week to 

 fourteen days, these eggs will hatch and become 

 living parasites, that in their turn will follow 

 the natural instincts of their being, and continue 

 the process, already explained, of preserving 

 their species. It is possible that enough of this 

 solution may be retained in the wool, to anni- 

 hilate a portion of the young acari as they hatch, 

 but experience proves that this cannot be de- 

 pended upon, for the wool continues its growth 

 and forms a layer next to the skin, which is 

 entirely free from the dip and protects the incip- 

 ieri^t breeders of the disease as they come from 

 the shell. 



Therefore if the shepherd thinks that his labor 

 has ceased with the first dipping and the appar- 

 ent checking of the disease, he will be sadly dis- 

 appointed, as well as surprised, to find it break- 



