40 



THE BEGINNINGS OF LIFE, 



It has been ascertained very definitely by the expe 

 riments of Helmholtz and of M. Schiff, that the trans. 

 mission of a stimulus through a nerve is marked by a 

 rise of temperature therein; whilst the extremely inte. 

 resting experiments of Dr. Lombard seem to show that 

 a similar rise of temperature takes place in the brain 

 itself ^^ when it is in a state of activity. Liebreich 



pour fournir k rinjection d'une manibre continue, une provision de 

 sang arteriel, on parviendrait sans peine h. entretenir la vie ind^finement 

 dans quelque troncon que ce soit ; et par cons^'quent, aprbs la d&api- 

 tation, on I'entretiendrait dans la tete elle-meme avectoutes les fonctions 

 qui sont propres au cerveau. Non seulement on pourrait entretenir la 

 vie de cette mani(^re, soit dans la tete, soit dans toute autre partie isolee 

 du corps d un animal, mais on pourrait I'y rappeler aprfes son entike 

 extinction.' These predictions of Legallois have received a most re- 

 markable verification by the experiments of Brown-Sdquard, which are 

 thus referred to by M. Gavarret :— * Sur un chien, M. Brown-Sequard 

 separela t§te du tronc; il attend Z^wzV ou dix minutes jusqu'a ce que, 

 depuis quelques instants, le bulbe rachidien et le reste de I'encephale 

 aient bien dvidemment perdu toute trace appreciable d'excitabilit^ ; puis 

 il, pratique des injections r^it^rees de sang defibrin^ et oxygend a la fois 

 dans les artbres caro tides et dans les vert^brales. Quelques mouvements 

 d&ordonn& apparaissent au bout de deux ou trots minutes, puis les 

 muscles des yeux et de la face executent des mouvements coordonnds 

 v^ritables manifestations de la vie, qui tendent k faire admettre que les 

 fonctions cdr^brales se sont r^tablies dans cette tete completement sepa- 

 r^e du tronc' (Loc. cit. p'. 237.) 



1 See ' Journal de Physiologic,' t. i. 670. Intellectual and emotional 

 activity alike produced a rise of temperature, which was always most 

 appreciable over the posterior part rather than the frontal region of the 

 head. We must suppose that the heat detectable in these cases is some 

 surplus portion of that set free in the blood of the part— a porti 

 which has escaped modification into nerve-force. The muscle, as we 

 have seen, is only capable of utilizing a portion of the heat actually 

 liberated. But if the analogy between the mode of action of the muscle 

 and the nerve-centre does not hold— and there is still much room for 



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rather from an 

 the blood to the 

 reasonable to su 

 virtae of their ac 

 of waste 2; and, 



evidence in 



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diminution of p 

 which had long b 



doubt on this subjec 

 mere increased afflu) 

 n'liicii is liberated d 

 nerre-tissne itself, 

 ' ' On the Influeni 

 fm. Acid by the 

 Society,' 1869, p. ig. 



' The researches ( 

 "I^dical Science,' 



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