388 HUMAN ANATOMY 



sensory nerves, and seek to determine whether the unfavorable 

 conditions have not retarded the growth-process in this division of 

 the nervous system. If the results of such observations are positive, 

 we may expect to find a corresponding modification in man, when 

 the human body during the period of growth is subjected to unfa- 

 vorable conditions of a similar nature. As a matter of fact, such 

 unfavorable conditions do exist in the crowded quarters of our 

 larger cities, and it seems highly probable that we have there in 

 progress examples of partial starvation quite comparable with the 

 experiments conducted in the laboratory. Under these circum- 

 stances, it is important to discover in the case of our animals how 

 far a subsequent return to normal food conditions will modify the 

 anatomy of a nervous system which has been subjected to proteid 

 starvation for some weeks. At present there are no observations 

 which indicate whether or no recovery in the nervous system will 

 take place, and it will probably require some time to reach a definite 

 conclusion. The work necessary for a determination of the ana- 

 tomical changes exhibited by the animals alone constitutes by no 

 means a light task, since in order to obtain reliable results and to 

 eliminate the factor of individual variation a series of individuals 

 must be examined, and it requires a very definitely sustained interest 

 to carry through the long line of enumerations necessary for such 

 an investigation. The examination of the growth of the nervous 

 system in animals subjected to definitely unfavorable conditions 

 is, however, only one part of the work. 



It will be necessary to contrast the changes there found with the 

 effects of special feeding, care, and exercise in other groups, in order 

 to see how far above the ordinary form the nervous system can be 

 anatomically improved by any such treatment; and experiments 

 in this direction are already being conducted by Dr. Slonaker. Of 

 course, the results which have been obtained and may be obtained 

 on the animals studied in this way should not be directly applied 

 to the case of man, because it seems quite evident that the higher 

 organization of man is responsible for his ability to resist to a re- 

 markable degree the disturbing effects of an unfavorable environ- 

 ment. The impression is abroad that the reverse is the case, and 

 that it is man who is more responsive to unfavorable surround- 

 ings. I believe, however, that this current view will prove to be 

 incorrect, for the lower mammals at least, and that when we place 

 such animals where the conditions for them are abnormal, their 

 limited powers of adaptability lead them to be more seriously 

 affected than are animals which are more complexly organized. 

 If such is the case, variations of the same amount should not be 

 expected to appear in man, but there is every reason to assume that 

 the variations which do appear will be of the same general character, 



