702 



SCIENCE. 



[N. S. Vol. XX. No. 517. 



animals are absent, only those oecurxing 

 with thickest skin— least apt to lose watei' 

 by transpiration— such as certain snakes, 

 lizards and hard-shelled beetles. In gen- 

 eral, in studying the geographical distribu- 

 tion of animals in environments presenting 

 extreme conditions we find that they clear- 

 ly have been selected from groups present- 

 ing the most favorable characteristics. All 

 of this indicates that, often at least, the 

 already existing morphological conditions 

 have determined the fitness of a species to 

 cope with the environment— morphological 

 characteristics have determined geograph- 

 ical and climatic distributions. 



Morphology as the science of form is 

 often contrasted with physiology, the sci- 

 ence of function. Yet between the two is 

 the closest possible relation, because an 

 organ implies a function and every mor- 

 phological characteristic has a correspond- 

 ing physiological characteristic. As phys- 

 iological characteristics are transmissible 

 in the same way as morphological, we may 

 think of any individual as being made up 

 of such functional characteristics, just as a 

 molecule is made up of atoms, and in the 

 transfer from one race or species of a set 

 of morphological characteristics we trans- 

 fer likewise the corresponding set of phys- 

 iological characteristics. Thus to return 

 to poultry, we find the rate of growth, the 

 age at maturity, the egg production, the 

 brooding instinct and the resistance to dis- 

 ease to be characteristics of various races, 

 and it is quite possible to combine such 

 characteristics— in so far as they are not 

 incompatible — in various ways. Thus we 

 have poultry that mature early, lay many 

 eggs and are not broody— of these the 

 white Leghorn is a good example. Or, 

 we may have poultry that grow large, ma- 

 ture 'late, lay throughout the winter and 

 are very broody— such are the Cochins. 

 This similarity in capacity for making 

 combinations which we see between phys- 



iological and morphological characteristics 

 proves their close kinship and the unscien- 

 tific nature of the division which would 

 relegate their study to distinct sciences. 



What is true of domesticated races is 

 true also of wild species. Biology has 

 suffered from the circumstance that species 

 have been studied almost exclusively from 

 dead specirhens. Attention is focussed on 

 proportions in the dimensions of bones, on 

 number of spines, on antennal joints, on 

 shell markings and so on, and we seem to 

 have overlooked entirely the fact that all 

 these characters constitute only one face of 

 the shield. The structural descriptions of 

 the systematist give us a no more adequate 

 idea of the characteristics of species than 

 does the sight of this exposition on a Sunday 

 when all wheels are stopped and only the 

 form, beautiful and grand as it is, remains 

 give us an adequate idea of it. And so 

 in the study of species we can not under- 

 stand the form characteristics without con- 

 sidering also the function characteristics. 

 I may illustrate this by some studies which 

 Miss Smallwood has been making at Cold 

 Spring Harbor. She started with a species 

 of Amphipoda — Talorchestia longicornis — 

 that lives on the beach where it is rarely 

 covered by the tide. After studying its 

 form and behavior for several months she 

 investigated a second species of the same 

 family of Orchestidse, Orcliestia palustris, 

 that lives on the salt marsh to the limit of 

 the highest tides. After studying this for 

 some weeks with respect to behavior corre- 

 lated with structure she has begun on still 

 a third species of the same family, Alor- 

 chestes, which is a typical aquatic organ- 

 ism. The instructive thing that comes out 

 of her studies is that in just the same way 

 as these species difi'er in structural char- 

 acteristics they differ in functional char- 

 acteristics and the two kinds of differences 

 go hand in hand and they have to be 

 studied together to "be fully intelligible 



