VESTIGIAL PARTS. 71 



veterinary surgeon knows ; for horses frequently refuse 

 food, set their coats, and get out of condition simply 

 from the trouble caused by these teeth : as soon as they 

 are removed the horse rapidly improves and gets once 

 more into condition. This vestigial pre-molar of the 

 horse is often omitted in drawings (even in veterinary 

 works) of the teeth of the horse. 



It has been clearly shown by the researches of 

 Albrecht that man has a smaller number of teeth than 

 he formerly possessed. The mouth is often the seat of 

 a defect known as cleft palate ; not infrequently children 

 affected with complete clefts are furnished with three 

 incisor teeth in the jaw which is cleft, and occasionally on 

 both sides. In rarer cases an extra incisor tooth may 

 make its appearance taking rank, and being co-equal 

 with, the normal incisors. This matter has been 

 inquired into by many competent observers, and its 

 occurrence is beyond all doubt The most satisfactory 

 explanation of the phenomenon seems to be that 

 offered by Albrecht ; it is to this effect : man normally 

 inherits in each upper jaw germs of three incisors, one 

 of these usually becomes suppressed ; in cases of cleft 

 palate there is more space for the teeth to develop and 

 a greater supply of blood to the parts adjacent ; these are 

 circumstances favourable to the full development of the 

 germ of the third incisor. 



The fact related above is of sufficient interest in itself; 

 it is also of importance in a general way because there is 

 good reason for the belief that the germs of other teeth 

 have been suppressed in the mouth of man, and that the 

 wisdom teeth are slowly undergoing this process. It has 



