170 REPORT — 1859. 



the established doctrine respecting the exclusively sensorial function of the posterior 

 nerves. 



To resume in a few words the conclusions of this paper : — If the supposed essen- 

 tial distinction between the two nerves issuing from the anterior and posterior 

 columns of the spinal cord exist at all, it must be either a distinction of property, 

 inherent in the nerves, or of function, resulting from anatomical distribution. But 

 there is no distinction of property ; both nerves having identical structure must have 

 identical properties ; and experiment has shown that both nerves are capable of 

 conducting in both directions. Nor is there any essential distinction of function ; 

 both nerves agree in being distributed to the spinal cord, which makes them both 

 sensory in function ; and although the two nerves differ in their peripheral distribu- 

 tions, the one going to muscles, which makes it pre-eminently a motory nerve, and 

 the other to the skin, where the muscles are very insignificant, which makes it only 

 motory in a small degree, yet these variations in degree are not such as would imply 

 the essential distinction universally attributed to the two nerves. Both nerves are 

 sensory and both are motory ; yet inasmuch as the skin- nerves, from the fact of their 

 distribution, are the channels of more intense and more various sensations than the 

 muscle-nerves can be, these skin-nerves may continue to be styled sensory, by way 

 of convenience; and inasmuch as the muscle-nerves are the channels of more ener- 

 getic and more various movements than the skin-nerve can be, they may properly 

 continue to be styled motory nerves. But it is important to recognize that the verbal 

 distinction between the two nerves represents no essential distinction. The poste- 

 rior nerves are skin-nerves, and are the channels for the sensations and contractions 

 of the skin ; the anterior nerves are muscle-nerves, and are the channels for the 

 sensations and contractions of the muscles : this is the distinction between them. 



On the Homologies of the Coats ofTunicata, with remarks on the Physiology 

 of the Pa/Hal Sinus System o/'Brachiopoda. By J. D. Macdonald. 



An Experimental Inquiry into the Action of Alcohol on the Nervous System. 

 By W. Marcet, M.D., F.R.S., Assistant Physician to the Westminster 

 Hospital, §c. 



The object of the communication is to determine whether the action of alcohol is 

 transmitted to the nervous centres by means of the circulation, or whether this 

 action depends on the contact of the fluid with the nerves of the stomach. 



The author divides into three series the experiments he has undertaken on the 

 subject in question. 



In the first series he investigated the action of alcohol on the healthy animal, 

 choosing the frog on one hand, and the dog on the other. In the second, he cut 

 through the nerves supplying the parts in contact with or immersed in alcohol, leaving 

 the circulation undisturbed ; in which experiments frogs only were used. In the 

 third series the circulation of the parts immersed in alcohol was arrested, and the 

 action of the poison on the nervous centres was noted. Frogs and dogs were sub- 

 mitted to these last experiments. 



The specific gravity of the alcohol used was 833. The posterior extremities of the 

 frogs were immersed in alcohol of this strength up to the commissure of the thighs. 

 Alcohol, diluted with an equal bulk of water, or less in some experiments, was in- 

 jected into the stomach of dogs by means of a syringe. In order to prevent the cir- 

 culation of the stomach from taking place, the author tied the thoracic aorta of dogs 

 by means of a peculiar kind of aneurism needle invented by Mr. Trant of Dublin. 

 ' The following were the results obtained from these investigations. 



Results from the first series of experiments. 



1st. When the hind legs of a frog are immersed into alcohol, the sensation and 

 respiration of the animal cease in from ten to thirteen minutes. 



2nd. The posterior extremities of the frog, which are in contact with alcohol, 

 become insensible and powerless sooner than the other parts of the body. 



3rd. A shock occasionally takes place shortly after the immersion, which consists 





