124 



ANDREWS. 



Selection of Environment by the Living Substance. 



I have shown that throughout the Metazoan mass, as through- 

 out the Protozoan, physiological function is correlated with areal 

 organization of the elements of the emulsive foam. In the 

 former as in the latter, organs are areas of vesicular organiza- 

 tion ; and in either, all such areas however fleeting are true 

 substance organs. 



In the higher forms, there is a more fixed and definite habit of 

 structural arrangement, certain relative localities being fixed for 

 grouping certain discontinuous elements in a certain way ; while 

 in the lower forms, locality for any given mode of organization 

 may be as unstable within certain limits as the substance itself. 



[ii6] Nothing new by way of minute structure visible with 

 the microscope was seen in the most complex of the series of 

 organisms examined ; but merely a more extended and multiple 

 and stable organization of the foam elements, and of the habit 

 of the substance in correlation with these things ; the contact 

 relations thus brought about resulting in quantitative and quali- 

 tative emphasis of physiological function, and a more extended 

 control by the substance as organism of its general environ- 

 ment as a source of supply, or control of its own use of supplies 

 obtained from that source. 



[117] We are so used to limit our notions of environment of 

 living beings to the external world, and to ignore that which 

 forms for the substance a large internal world of contacts and 

 opportunities ; so used to think of environment as in a way 

 dissociated from — nay, even antithetical to — organisms, that 

 it may be difficult, perhaps, to think all at once of external 

 environment as a mass of heterogeneous conditions bearing to 

 the external contact surface of organisms the same relation 

 that the blood of a frog, for instance, or the contents of a food 

 sac of amoeba, or even of an alveolus of a structure of Biitschli, 

 bears to the substance surrounding it. The ancient warfare of 

 the race with environment hinders us, indeed, in grasping the 

 truth of these relations and realizing that external environment 

 is to the substance as organism akin to the sum of internal en- 

 vironment for the substance as such. 



