]'ebruaby 4, 1921] 



SCIENCE 



101 



hibition of the expiratory muscles and vice 

 versa, and he goes on to make the suggestion 

 that a similar relationship must prevail in 

 the case of all antagonistic muscles such as 

 the extensors and flexors of the limbs. Some 

 ten years later Sherrington gave the necessary 

 demonstration that this interrelation does 

 hold with the muscular antagonists, that the 

 contraction of the one is accompanied by the 

 inhibition of the other and he designated this 

 relationship under the term of " reciprocal 

 innervation." Meltzer meanwhile had been ac- 

 cumulating instances of this combined action 

 of excitation and inhibition, but he neglected 

 at that period to apply a distinctive name to 

 this kind of correlated activity. There can 

 be no doubt that when it is possible to label 

 an idea with an appropriate designation its 

 currency in the scientific world is greatly 

 facilitated. In his paper on " The Self-Eegu- 

 lation of Respiration" read before the Amer- 

 ican Physiological Society in 1889 and pub- 

 lished in the New Yorh Medical Journal and 

 under a different title in the Archiv. fur 

 Phydologie he describes experiments intended 

 to show that two kinds of afferent fibers exist 

 in the vagus nerve, one exciting and the 

 other inhibiting inspiratory movements. He 

 used this fact to modify the Hering-Breuer 

 theory of the seK-regulation of the respira- 

 tions by assuming that the expansion of the 

 limgs stimulates both groups of fibers. The 

 resultant effect, as in the case of the simul- 

 taneous stimulation of the motor and in- 

 hibitory fibers to the heart, is a dominance 

 of the inhibitory effect, thus cutting short the 

 inspiration and bringing on an expiration. 

 But after the inhibition ceases the excitatory 

 fibers, which, like the acceleratory fibers of 

 the heart have a long after action, come into 

 play and start a new inspiration. In his first 

 general paper on inhibition this idea of a 

 combined action of opposing processes is ex- 

 tended by the citation of nuxaerous instances 

 taken from physiological literature and is ex- 

 panded into a general theory which makes 

 inhibition a universal property of irritable 

 tissues. 



"I entertain and defend the view that the phe- 

 nomena of life are not simply the outcome of the 

 single factor of excitation, but they are the result 

 of a compromise between two antagonistic factors, 

 the fundamental forces of life, excitation and in- 

 hibition. ' ' 



That is to say, whenever a tissue is stim- 

 ulated two different processes are aroused, 

 one leading to functional activity and one to 

 a suppression of activity. As to the nature 

 of these processes very little is said. He was 

 not satisfied with the Hering-Gaskell con- 

 ception that excitation follows or is an ac- 

 companiment of catabolic changes while in- 

 hibition is due to processes of an anabolic or 

 assimilative character. He goes only so far 

 as to assume that both processes are con- 

 cerned with the kinetic and potential energies 

 of the system, that excitation facilitates the 

 conversion of ijotential to kinetic energy 

 while inhibition hinders or retards this con- 

 version, like the turning off or on of a stoI^ 

 cock. Nor was he satisfied with Sherring- 

 ton's term of reciprocal innervation to de- 

 scribe all of the phenomena he had in mind. 

 While this phrase is a suitable designation 

 for the relationship between physically an- 

 tagonistic muscles such as the fiexors and 

 extensors it is less appropriate in other cases, 

 for example the simultaneous phases of con- 

 traction and inhibition exhibited in peri- 

 stalsis. In later papers he suggested first the 

 term crossed innervation borrowed from von 

 Basch, but subsequently adopted the designa- 

 tion of contrary innervation as more appli- 

 cable to the whole series of phenomena which 

 he was considering. This process he believed 

 is universal in its action — it is "manifest in 

 all the functions of the animal body." More- 

 over his experience and observation as a prac- 

 tising physician led him to believe that "a 

 disturbance of this law is a factor of more 

 or less importance in the pathogenesis of 

 many disorders and diseases of the animal 

 body." In this way he would explain in part 

 at least the muscular incoordination in tabes 

 and the gastric crises of that disease, as well 

 as gastric and intestinal colic in general. If 

 the orderly sequence of a peristaltic wave is 



