CHAPTER XXVIII 



THE COOPERATIVE OR SOCIAL SYSTEM AMONGST 

 LOWER ANIMALS AND MAN 



Amongst the lower invertebrate classes the rudimentary 

 character of the nervous system is evidently correlated with 

 a want, or a feeble indication, of cooperative effort. But the 

 manner in which large masses of individuals that constitute 

 a species, amongst the coelenterate, echinoderm, and worm 

 series, live together in complete tolerance, at least, would sug- 

 gest that certain chemotactic and other energizing currents, 

 of like value in each set of individuals, contribute to a certain 

 neutrality of action in feeding and in other life processes. 

 Amongst these also the reproductive products are shed into 

 the water, and so the maternal or paternal 'acts are practically 

 non-existent. 



But with advancing cumulation of a nervous system, a 

 distinct regard and care for the eggs are first shown; next for 

 these till the period of hatching ensues; next for the eggs and 

 the callow hatched brood, as among some social insects; finally 

 for each stage in the process of growth, from the egg to the 

 maturing adult, as amongst many ants. Increasingly com- 

 plex evolution of the nervous system, and increasing care for 

 the offspring of each species concerned, are thus correlative 

 developments .in nearly every instance. 



In comparing, however, the exhibitions and relative value 

 of competition and cooperation along the animal scale, it 

 should be noted that richness in individuals, and steady ex- 

 pansive distribution of them over the earth, counts far more 

 powerfully in the end than does richness or variety of species, 

 specially when such species are carnivorous in habit. In no 

 group is this more strikingly verified than amongst the most 

 evolved of all insects, the ants. Regarding these, Wheeler 



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