ACADEMY OF SCIENCES] BIOGRAPHY 7 



of vibration is one of the normal and essential conditions of life — like temperature, for example. 

 Furthermore, he conceived that the rate of the heart beat is adjusted, on the one hand, to furnish 

 the optimum vibratory conch tion for the cells of the organism, and, on the other, to give a mechan- 

 ical vibration which is destructive toward foreign cells, such as invading bacteria. He con- 

 sidered that this constitutes one of the defensive mechanisms of the body, an idea which I 

 fancy none of his fellow workers has adopted. 



In one of the last, if not the very last paper that he wrote, a paper pubhshed only two 

 months before his death, he announced a most interesting discovery, namely, that removal of 

 both superior cervical ganglia in rabbits is followed by death in about 90 per cent of the cases. 

 His experiments, as usual, are described with care and exactness, but he does not hesitate to 

 speculate with some boldness upon the possible explanations of this remarkable result, and it 

 is to be noted that the two chief hypotheses that he advanced are of a kind that probably do 

 not at once commend themselves to his fellow physiologists. He suggests, in the first place, 

 that these ganglia "contain a principle which is essential for the maintenance of life" — that is, 

 they produce an essential internal secretion. In the second place, to account for the pulmonary 

 lesions exhibited by the operated animals, he assumes that the ganglia normally send impulses 

 to the respiratory centers through which the orderly play of the antagonistic (abductor and 

 adductor) muscles of the larynx are controlled. In the absence of this controlling influence 

 there is a disharmonious action of the muscles, a disorder of the law of contrary innervation, 

 which, as in the case of section of both vagi, leads in some way, not clearly understood, to an 

 infection of the lungs. These and like examples indicate clearly how experimental results 

 tended to stimulate his imagination, as they must do with every worker whose soul is in his 

 work. He held hard to his facts, and insisted that other workers should do the same; but on 

 the basis of these facts his intense and eager mind sought to discover the larger principles that 

 control the hfe of the organism. Some of his theoretical speculations were more fortunate in 

 finding a prompt acceptance and application among his fellow workers. Thus, in his Harvey 

 lecture, 1906, on " The factors of safety in animal structure and animal economy," he made a 

 most happy application of this term, used in engineering, to describe the reserve powers exhibited 

 by the mechanisms of the body. While the general conception that he developed had no doubt 

 occurred to others, no one before him, so far as I know, had clearly visualized the great impor- 

 tance of these reserves in the adaptation of the organism to the changing conditions of its 

 environment. The apt phrase that he selected to designate this property found an immediate 

 acceptance in scientific medical circles the world over. One meets the expression now con- 

 stantly in current literature, accompanied usually by a grateful acknowledgment to the author 

 who first suggested its use. The mere term itself, "factor of safety," has proved most useful 

 as a convenient and suggestive form of expression, but much more valuable than this is the 

 emphasis it has given to a great general biological law expressing the way in which an organism 

 is adapted to meet environmental stresses. 



In his paper on " Bronchial asthma as a phenomenon of anaphylaxis " (Journal of American 

 Medical Association, September 17, 1910) Meltzer made a theoretical suggestion as to the 

 nature or cause of true bronchial asthma which not only attracted wide attention in medical 

 circles, but has proved to be a real assistance in the understanding and treatment of a trouble- 

 some disease. 



The most important of his contributions in later years are contained in three series of 

 researches: One dealing with the action of adrenalin upon the blood vessels and the muscles 

 of the iris ; one with the inhibitory action of magnesium sulphate and the antagonistic effects of 

 calcium salts; and one with his method of artificial respiration by pharyngeal and intratracheal 

 insufflation. The first series consists of eight or nine papers, mostly in collaboration with his 

 daughter. They showed in this work that the temporary action of adrenalin upon the blood 

 vessels may be converted into a long-lasting effect, in the case of the ear vessels, if these vessels 

 are first denervated by section of the vaso-motor fibers in the sympathetic and the third cervical 

 nerve. A more striking result still was obtained for the iris. In the mammal subcutaneous 

 injections of adrenalin in moderate doses have no effect upon the size of the pupil, but if the 



