234 APPENDIX. 



falling off of the hair occasioned by performing extra labour, it is 

 natural to think that instances of it would be more frequent than 

 they are ; as it is rare to see one of them in the course of seven or ten 

 years. I have seen a whole house of those animals that had nothing 

 on the surface of their bodies but the fine soft down ; all the long 

 hairs having molted off. This and every other deviation from the 

 general run is undoubtedly owing to some particular disorder. 



