CLAUDE BERNARD 575 



All the part of the head that becomes hot after section of the nerve becomes 

 also the seat of a more active circulation. The arteries seem fuller and appear 

 to pulsate more forcibly; this is distinctly seen in the case of the rabbit in the 

 vessels of the ear. 



He reserves for further consideration " whether the vascular changes 

 are the cause or the effect of the rise of temperature." While the 

 work was published as experiments on animal heat, it is the first 

 clear and decided experimental proof for the vasomotor functions 

 of nerves. The operation had been performed for one hundred and 

 fifty years and the constriction of the pupil of the eye had been 

 noticed, but the increased heat and the dilatation of the arteries had 

 never before been observed. With this experiment, the true knowledge 

 of vasomotor nerves begins. 



This discovery caused a great stir in the scientific world and several 

 investigators proceeded to work on the subject independently. Brown- 

 Sequard proposed the correct interpretation of the phenomena that sec- 

 tion of the nerve caused a dilatation of the blood vessels and the dila- 

 tation allowed increased blood flow which resulted in an increase in tem- 

 perature and irritability. Bernard held continually that part of the heat 

 effect might be due to the influence of the nerves on the chemical ac- 

 tivities in the tissues. 



Several years later, working on the submaxillary gland, Bernard 

 observed that the blood coming from the gland was bright red, like ar- 

 terial blood when the chorda tympani nerve was stimulated, and that it 

 was dark, venous and small in quantity when the sympathetic nerve was 

 stimulated. Thus, he showed that the chorda tympani is a vasodilator 

 nerve causing dilatation and increased blood flow, while the sympathetic 

 is a vasoconstrictor nerve. This effect was shown to be true for other 

 glands. This was the first clear announcement of the presence of vaso- 

 dilator and vasoconstrictor nerves. 



Other lines of work occupied his attention, but the results do not 

 possess such fundamental value as those described above. He worked 

 on the physiological effects of curare, the arrow poison of the South 

 American Indians. Carbon monoxide poisoning was explained as due 

 to a stable combination of the gas with the red blood corpuscles. This 

 explanation was made before respiration had been explained as due to an 

 unstable combination of oxygen with the hemoglobin of the red blood 

 corpuscles. He presented a proof against the spontaneous generation 

 of life when that question was a vital issue in the scientific world. He 

 carried out some work on fermentation opposing Pasteur's views that 

 the living cell is necessary, thus anticipating Buchner's proof by twenty 

 years. 



Bernard began work when opportunities for research were scarce 

 and his chosen field was looked down upon and scoffed at, but he per- 



