970 



SCIENCE. 



[N. S. Vol, XI. No 286. 



3. Toward a study of the effect of envi- 

 ronment in inducing and modifying de- 

 velopmental processes. Experimental mor- 

 phology, experimental zoology, experimental 

 embryology, are new subdivisions of our 

 subject which express this tendency. It is 

 possible to subject developing animals to 

 the influence of various factors of the en- 

 vironment in order to determine their effect. 

 Developing eggs may be subjected to dif- 

 ferent temperatures, or to chemical solu- 

 tions of different sorts and strengths or to 

 the influence of electricity. In this way 

 we may find what influence each of these 

 factors has on development. Adult ani- 

 mals may be subject to similar changes of 

 environment. The results of such researches 

 are usually expressible by mathematical 

 symbols, such as geometric curves or alge- 

 braic equations. 



Such work is only in the beginning but 

 it may ultimately lead to such an analysis 

 of the environment as to enable us to as- 

 sign to each of its factors its proper value 

 as an element in organic development. 



Experimental work is also being directed 

 toward a determination of the internal fac- 

 tors of development, those which are resi- 

 dent in the animal itself and are not im- 

 pressed upon it by the environment. The 

 effect of the removal of portions of the de- 

 veloping egg, enables us to determine the 

 part taken by those portions in the normal 

 development of the whole egg. Others of 

 the internal factors of development may be 

 studied by direct observation (without ex- 

 periment) and by comparison. 



4. Toward a study of the activities of 

 animals. Animals exhibit many sorts of 

 activities that may be classified. Those 

 connected with the taking of food, with re- 

 production, with the rearing of young, with 

 construction of dwellings, with community 

 life and so on. "We are beginning to sus- 

 pect that many of these activities have fea- 

 tures that are common to large numbers of 



animals and that their origin and develop- 

 ment may be traced with as much certainty 

 as the origin and development of the organs 

 of the animals. Many of the activities of 

 man himself may doubtless be traced to an 

 origin in the lower animals and much light 

 thereby thrown on what we are pleased to 

 call human nature. 



Monographic work in its descriptive 

 branches, the study of variation experimen- 

 tal work, and the study and comparison of 

 the activities of animals seem then to be the 

 directions in which zoological research is 

 now turning. 



The phylogenetic phase has passed the 

 height of its development for the present 

 and must await the accumulation of new 

 data before it can again become dominant. 

 But since the study of phylogeny does not 

 really solve any philosophical question (but 

 only gives form to a question already as- 

 sumed to be solved) it is likely that it will 

 never again become ascendant. Time will 

 bring the solution of many of its problems, 

 but such solutions are likely in the future 

 to possess only a secondary interest. 



On the other hand the new lines of work 

 look toward the solution of the most im- 

 portant questions concerning the method of 

 origin of organic forms. 



Coincident with the gradual acceptance 

 of the evolution idea, and coincident with 

 the great development of morphological 

 and phylogenetic ideas in our universities, 

 there seems to have been a decline in popular 

 activity in natural history. This did not be- 

 come manifest immediately after 1859, but 

 began, perhaps, ten or fifteen years after 

 that date and has been in progress since 

 then, up very nearly to the present time. 



The most striking evidence of this de- 

 cline is afforded by the decay of natural 

 history societies. In this state Detroit and 

 Grand Rapids each formerly supported such 

 societies. They were well patronized, had 



