336 Analysis of Scientific Books. 



tained to be the case, but found them equally numerous with tXe 

 arteries themselves. 



" This discovery enabled me to institute an experiment, which 

 at once would decide in what degree animal heat was under the 

 influence of ganglionic nerves. 



" As I might be considered too partial an evidence respecting 

 the different results arising out of such an experiment, I contented 

 myself with superintending it, and made over the operative part 

 to Mr. Mayo, and his associate Mr. Caesar Hawkins, teachers of 

 anatomy in Berwick-street. The experiment was to consist in 

 dividing all the trunks of the nerves that supplied the velvet of 

 one horn, while those of the other horn were left entire ; and see 

 how far, under these circumstances, the horn would be liable to 

 any diminution of its heat. 



44 An hour after the nerves were divided, which was about three 

 o'clock, of July the 21st, the temperatures were examined, and so 

 on once a day, as long as there was a material difference between 

 them. This will appear, by the following diary, only to have 

 continued for five days. 



44 Forty-eight hours after the nerves were divided, the tempera- 

 ture of the horn was only 3° higher than that of the atmosphere. 



44 From the time the experiment was made, the deer was kept 

 in a small paddock with two companions. On the 26th of July it 

 had bruised the horn so much, on which the experiment had been 

 made, that the diary could no longer be continued, and that horn 

 was then the hottest of the two. 



44 Upon examination after death no union had taken place be- 

 tween the divided trunk, but it was evident from the recovery of 

 its heat, that some other connexion had been formed between the 

 nerves of the horn and those of the head. 



44 This will not appear surprising, when I mention that the 

 fallow deer, before they have antlers, shed their horns in June ; 

 and immediately after, they again begin to bud, and in the middle 

 of August are completely hardened. Those with antlers mew in 

 April or May, according to their keep, and at the end of August 

 are at their full growth. So that in the space of four months, all 

 the nerves that are to supply the deer's horns of a full head have 

 not only begun to form, and arrived at their full growth, but have 

 ceased to exist. This rapidity of growth accounts for their 

 recovering in five days from any check that can be given to 



