'618 M. Becquerel 07i the Relation of Natural Philosophy 



in the valley of the Rhone and al the Great Saint-Bernard ; tliat 

 a sojourn of many years in the higher regions of the Alps pro- 

 duces no sensible modification ; and that those animals which 

 were transported from Martigny to the hospice did not manifest 

 any difference in the temperature of their tissues. 



Now, inquiries have also been made upon the temperature of 

 the internal parts of animals, for the purpose of ascertaining if it 

 were not influenced by motion, and if there did not exist an or- 

 gan in which the temperature was higher than in the surround- 

 ing parts. It has been proved by experiment, that the contrac- 

 tions of the muscles disengage caloric ; that in warm-blooded 

 animals there exists a difference of about a degree between the 

 arterial and the venous blood ; and that the temperature in the 

 same system, whether arterial or venous, diminishes in propor- 

 tion as you recede from the heart, so that the heart is that part 

 which is endowed with the highest temperature. 



Physiological phenomena are influenced not only by heat, but 

 also by electricity, by atmospheric pressure, and by many other 

 physical and chemical causes. The mass of the facts which have 

 been observed are worthy of attracting the attention of the phi- 

 losopher. We shall now confine ourselves to the action of elec- 

 tricity, whose effects sometimes restore the phenomena of life. 



When we transmit an electrical current, either in the course 

 of the nervous ramificatiuus or in the opposite direction, and 

 when we maintain it either for a considerable time, or suspend 

 it for a longer or shorter period, that we may again renew it, 

 there are effects produced in these various circumstances which re- 

 veal to us an arrangement in the organization of the nerves, which 

 the most minute and delicate anatomical researches, even when 

 aided by the help of the microscope, have not been able to discover. 

 We find that the nerve, in its longitudinal direction, if we may 

 so express it, has a right side and a wrong, in this way at least, 

 that a feeble electrical current is easily transmitted in the direc- 

 tion of its ramifications, and only with difficulty in the opposite 

 direction. In the former alternative there is a contraction with- 

 out pain, and in the latter there is pain without contraction. 

 This fact is of great importance, for it seems to indicate that the 

 cause, whatever it may be, which produces the contractions. 



