124 Essay on Sheep. 



quadrupeds change their coats every year, and 

 indeed generally twice a year: the Merino 

 sheep never changes his coat; on the contrary, 

 it will continue to grow from year to year, and 

 at the end of the third year the fleece will yield 

 a three years crop, with little or no diminution. 

 This experiment has been tried in France, in 

 Switzerland, and in England, for the course of 

 three years successively, and always with the 

 same result. The wool of this sheep then re- 

 sembles in its duration human hair, and may 

 probably be subject to the same physical laws. 

 Human hair is affected by the tissue of the skin 

 through which it passes. In warm climates the 

 hair of man is generally black and coarse; in 

 cold ones we find flaxen, yellow, and various 

 shades of brown, to be the prevalent colours; 

 and even where the hair takes a deeper shade, 

 it is finer than the lank black hair of the south. 

 May not this be owing in some sort to the skin 

 being more braced in one and more lax in the 

 other? and will it not produce the same effect 

 upon the wool of an animal whose fleece is pe- 

 rennial, particularly if the food and air invigo- 

 rate at the very time that the climate braces 

 the fibres? It is said that the wool of the com- 

 mon sheep is sometimes coarser, as he is either 

 well or ill fed. This may happen if he is cither 



