Sir Everard Home on the existence', &c. 67 
by discovering nerves in both the foetal and maternal portions 
of the placenta. This discovery, I am proud to say, was not 
the result of accident, but of a regularly arranged plan for 
that purpose. 
In examining, at my desire, the structure of the horns of 
the fallow deer during their growth, while covered with 
velvet, Mr. Bauer found them abundantly supplied with* 
nerves. The circumstance of nerves being met with, where 
sensibility is not only unnecessary, but even where the parts 
are unfitted for their office till the nerves are removed ; which 
takes place as soon as the horns are full grown; makes it 
appear that nerves answer some other purposes in the animal 
oeconomy, besides regulating the actions of the arteries ; ah 
office which, many years since, I not only considered them to 
perform, but illustrated my opinion by the effects of irritation 
on the parvagum and great sympathetic nerve on the carotid 
artery. Since that time, by considering the incubation of 
the chick, I have been led to believe that the arteries are 
indebted to the nerves for their formation ; and so strong 
was the conviction on my mind of this being the case, that 
even the circumstance of the placenta, whose blood vessels 
are very numerous, having been suspected to have no 
nerves, did not induce me to abandon it ; since until it is 
proved that the placenta is devoid of nerves, there is no 
argument against me. This was a point, of all others, that 
no one could so well determine as Mr. Bauer. I therefore 
most earnestly requested him to employ his microscopical 
observations on this subject, and' supplied him with the 
placenta of a seal, in which the arteries and veins had been 
injected ; and as in that animal the umbilical vessels are not 
