24 



SCIENCE. 



[S. S. Vol. XXI. No. 523. 



Ijrepared to determine variations in the 

 nature of excesses or deficiencies, and in 

 this instance tlie question of deficiencies is 

 the one most easy to handle. 



The studies of Dr. Ilatai* on the partial 

 starvation of white rats duriug the grow- 

 ing period show that very definite changes 

 can be brought about in the nervous system 

 when these animals are deprived of proteid 

 food for several weeks. As a result of 

 such treatment, the total weight of the 

 nervous system is reduced much below that 

 of the normal rat. Such a result, however, 

 leaves two points .still undetermined; (1) 

 the general nature of the changes bringing 

 about a diminution in weight, and (2) the 

 parts of the system in which changes occur. 

 In testing our animal material by quanti- 

 tative methods, we shoiild in the first in- 

 stance direct attention to a possible de- 

 crease or arrest of growth in the afferent 

 system of sensory nerves, and seek to de- 

 termine whether the unfavorable conditions 

 have not retarded the growth process in 

 this division of the nervous system. If 

 the results of such observations are posi- 

 tive, we may expect to find a correspond- 

 ing modification in man, when the human 

 body during the period of growth is sub- 

 jected to unfavorable conditions of a sim- 

 ilar nature. As a matter of fact, siieh ma- 

 favorable conditions do exist in the crowd- 

 ed 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 lalioratory. Under these 

 circumstances, it is important to discover 

 in the case of our animals how far a sub- 

 sequent return to normal food conditions 

 will modify the anatomy of a nervous sys- 

 tem which has boon subjected to proteid 

 starvation for some weeks. At present 

 there are no observations which indicate 

 whether or no recovery in the nervous sys- 



*" I[;it;ii, A iiirriraii Journril of I'hysiolor/!/, Ifl04. 



tern will take place, and it will probably 

 require some time to reach a definite con- 

 clusion. The work necessary for a de- 

 termination of the anatomical changes ex- 

 hibited 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 re- 

 quires a very definitely sustained interest 

 to carry through the long line of enumera- 

 tions necessary for such an investigation. 

 The examination of the growth of the 

 nervous system in animals subjected to 

 definitely unfavorable conditions, is, how- 

 ever, 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 treat- 

 ment, and experiments in this direction are 

 already being conducted by Dr. Slonaker. 

 Of course the results which have been ob- 

 tained and may be obtained on the animals 

 studied in this way should not be directly 

 applied to the ease of man, because it seems 

 quite evident that the higher organization 

 of man is responsible for his ability to re- 

 sist to a remarkable degree the disturbing 

 effects of an unfavorable environment. 

 The impression is abroad that the reverse 

 is the case, and that it is man who is more 

 responsive to unfavorable surroundings. 

 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 seri- 

 ously 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 



