z//:^. 





THE BEGINNINGS OF LIFE. 



41 



HifF, 



"ve is 



the 



extreme^ 



^^ccm to 



place 



s% 



in the 



and M. Byasson think that such evolution of heat is 

 produced by an increased amount of chemical change 

 in the active parts; though the investigations of Dr. 

 L. H. Wood 1 go to show that (as was the case in the 

 activity of muscle) the liberated energy is not derived 

 from the oxidation of the nerve-substance itself^ but 

 rather from an oxidation of the pabulum supplied by 

 the blood to the functionally active parts. It is quite 

 reasonable to suppose^ however^ that nerve-organs^' by 

 virtue of their activity, should undergo a certain amount 

 of waste 2^ and, probably, it is this of which we get 



1 toil te autre parti' evidence in the observations of Liebreich as to the 



diminution of protagon in parts of the nervous system 

 which had long been in a state of uninterrupted activity. 



avectouteslesk 

 )n pourrait entreie 



rtpel^r apr^s sone 

 ave received ams 

 ■o\vn-S^quard,rf. 

 lien, M. Brown-S 

 minutes jusqu'act 

 : le reste de Fencf 



•ible d'excitabiEte: 



rin^ et oxygenei- 



QuelquesiDOiiTt: 



X frois minutes, F 

 niouvements coo^ 



doubt on this subject — then the local increase of heat may be due to 

 mere increased afflux of blood, either alone or supplemented by heat 

 which is liberated during the molecular changes taking place in the 

 nerve-tissue itself 



1 ( 



On the Influence of Mental Activity on the Excretion of Phos- 

 phoric Acid by the Kidneys.* (' Proceedings of Connecticut Medical 

 Society,' 1869, p. 197.) 



^ The researches of Professor Haughton (' Dublin Quarterly Journal 

 h. faire admettref of Medical Science,' i860) and also of M. Byasson (' Thbse de Paris,' 



tele CO 



mpletenie^' 



^ellectualande^^' 



.-hich was ^ 

 he frontal re^ 



of the part^; 

 The ni^=*' 



e o( action <^^, 

 , is still i^^^ 



1868, No.. i62)-have shown that the same individual during periods in 

 which he has undergone much intellectual labour and a minimum of 

 muscular exercise, passes as much or even more urea than during other 

 similar periods when there has been much muscular- exertion and a 

 minimum of intellectual labour. The analyses of M. Byasson go to 

 show that the same individual, under the influence of the same diet, 

 passed in 24 hours the following quantities of urea : 



During a period of rest 20*46 grms. 



ion 



During a period of muscular labour 

 During a period of cerebral activity 



22*90 

 23-88 



5? 



9) 



