CHAPTER VI 

 HARMFUL EFFECTS OF CROWDING UPON GROWTH 



Our knowledge concerning the methods of aggregating and the 

 factors conditioning the formation of aggregations has grown steadi- 

 ly and gradually, as has our information concerning their integra- 

 tion. On the other hand, marked advance has been made since 1920 in 

 the investigations of the physiological effects which such aggregations 

 produce upon the individuals of which they are composed. The type 

 and extent of such effects make one of the crucial tests of the impor- 

 tance of the phenomena. If these aggregations are merely forced 

 reactions resulting from limited space or from blind tropistic be- 

 havior, or if they result only as an expression of a social appetite or 

 instinct, their significance is more remote and the problem of their 

 origin is more difficult of solution than if they can be shown to have 

 group value even in their poorly integrated stages. Failure to ob- 

 serve such values for many aggregations led Deegener to conclude 

 that their formation must be due to some inexplicable instinct. 



In the investigation of this problem we must first inquire whether 

 or not the aggregations with which we are deahng have positive or 

 negative survival value which can be recognized. Even if positive 

 survival value is found in a number of cases, the problem is by no 

 means solved; but the methods to be used in its solution will be more 

 clearly indicated than if we are forced to rely upon the postulate of a 

 former survival value, of which the only remaining evidence is a 

 weak social appetite persisting frequently in the face of present 

 negative survival values. 



Even with the recently devised methods of analysis, the harmful 

 effects of such aggregations are frequently more easily apparent than 

 are the benefits. To the eye of the naturalist depending on field ob- 

 servation for his data, benefits do not become obvious until the ag- 

 gregation is sufficiently well integrated so that members may be 

 warned of the approach of danger by some group attribute, such as 



