G. GENERAL NATURAL HISTORY AND ZOOLOGY. 233 



the finder touch. He therefore is led to believe that there is 

 another form of matter present during life, which exists in 

 the condition of vapor 01* gas, which pervades the whole per- 

 sonal organism, surrounds, as an enveloping atmosphere, each 

 molecule of nervous structure, and is the medium of all mo- 

 tion communicated to or from the nervous centres. 



The source of this refined matter in the body he considers 

 to be the blood, and he looks upon it as a vapor distilled from 

 the blood, as being persistently formed, so long as the blood 

 circulates at the natural temperature, and as being diffused 

 into the nervous matter, to which it gives quality for every 

 function performed by the nervous organization. In the 

 closed cavities, containing nervous structure, the cavities of 

 the skull and spinal column, this gaseous matter, or ether, as 

 he terms it, sustains a given requisite tension ; in all parts of 

 the nervous structure it surrounds the molecules of nervous 

 matter, separates them from each other, and yet is between 

 them a bond and medium of communication. 



In estimating and defining the physical properties of this 

 nervous ether he suggests that it is a gas or vapor, having in 

 its elementary construction carbon, hydrogen, and possibly 

 nitrogen. He thinks that it is condensable under cold, mov- 

 able under pressure, diffusible by heat, insoluble in the blood, 

 and holding, at the natural temperature of the body, a ten- 

 sion requisite for natural function. In his opinion it is re- 

 tained for a longer time after death in cold-blooded than in 

 warm-blooded animals, and longer in warm-blooded animals 

 that have died in cold than in those that have died in heat. 



It is not, according to his idea of it, in itself active, nor an 

 excitant of animal motion in the sense of a force, but it is 

 essential as supplying the conditions by which the motion is 

 rendered possible ; as serving as a conductor of all vibrations 

 of heat, light, sound, electrical action, and of mechanical fric- 

 tion. It holds the nervous system throughout in perfect ten- 

 sion during perfect states of life. By exercise it is disposed 

 of, and when the demand for it is greater than the supply, its 

 deficiency is indicated by nervous collapse or exhaustion. It 

 accumulates in the nervous centres during sleep, bringing 

 them to their due tone, and thus rousing the muscles to 

 awakening or renewed life. The body, fully renewed by it, 

 presents capacity for motion, fullness of form, and life. The 



