Miscellaneous Intelligence. 73 



III. Miscellaneous Scientific Intelligence. 



1. The Integrative Action of the Nervous System • by Chas. 

 S. Sherrington, Professor of Physiology in the University of 

 Liverpool. Being the Silliman Memorial Lectures for 1904 at 

 Yale University. Octavo, 393 pages with numerous graphic 

 records and index of bibliography. New York (Charles 

 Scribner's Sons). — The problem dealt with in these lectures is 

 postulated thus : " In the multicellular animal, especially for those 

 higher reactions which constitute its behaviour as a social unit 

 in the natural economy, it is nervous reaction which par excel- 

 lence integrates it, welds it together from its components, and 

 constitutes it from a mere collection of organs an animal individ- 

 ual." The elementary form of nervous system, the simple nerve- 

 net exemplified in Medusa, affords merely diffuse conduction. 

 It obevs the " all or none " law, and affords the animal only a 

 single invariable response to all adequate stimuli whatever their 

 character or point of application. Contrasted with this simpli- 

 city and uniformity, the wide variety of response by which the 

 higher animals adjust themselves to, and indeed dominate their 

 environment, is not merely due to the greater complexity of their 

 "effector " mechanisms, but is peculiarly the endowment afforded 

 by the " synaptic " nervous system. The unit reaction in nerv- 

 ous integration, the simple reflex, is probably a purely abstract 

 conception, but a fiction which is essential to the analysis of com- 

 plex coordinated reactions. Its machinery consists of (1) a 

 "receptor" organ which is usually endowed with a specialized 

 irritability so that because of its low threshold value for one 

 form of stimulus and relative insensibility to'all other changes 

 of the environment it affords a selective character to the reaction 

 which it evokes. (2) A " private path " or afferent neurone 

 connecting the "receptor" with the central grey matter of the 

 nervous system. (3) The efferent neurone which the author 

 denominates the "final common path" because upon it debouch 

 all the " private paths " and through it are effected all reactions. 



(4) The "effector" organ, muscle fiber or gland cell. And 



(5) between the afferent and efferent neurones a "synapse" or 

 surface of separation between their interlaced but non-continu- 

 ous dendrites. Nerve fibers are mere conductors. Bethe's 

 experiment on Carcinus shows that the perikarya (nerve-cell 

 bodies) are not responsible for the features characteristic of 

 reflex arc conduction. In the "synapse" therefore must be 

 found those properties upon which depend such phenomena as 

 latency, after-discharge, summation, "Bahnung" fatigue, inhibi- 

 tion, tonus, refractory phase, and the manifold relations between 

 intensity of stimulus and intensity of reflex reaction. These 

 phenomena are in turn discussed on the basis of the author's 

 illuminating investigations on the " spinal " dog. Especial atten- 

 tion is devoted to the phenomena of " interference " at the 

 "synapse" by which when any private path because of excita- 



