April 14, 1916] 



SCIENCE 



513 



these hypotheses ignore one very funda- 

 mental difference between the organism 

 and the crystal. The unity and order of 

 the organism are fundamentally dynamic 

 and associated with chemical change, and 

 when the characteristic chemical changes 

 cease the unity and order disappear, ex- 

 cept in so far as the anatomical record 

 of dynamic activity may persist for a 

 longer or shorter time. The unity and 

 order in the crystal are static and when 

 chemical change begins they disappear. 



In this brief survey I have endeavored 

 to bring out the fact that our biological 

 theories of the individual, so far as they 

 are not avowedly vitalistic or dualistic, 

 are largely static and anatomical in fact or 

 in implication, rather than dynamic. They 

 are, in short, hypothetical descriptions of 

 the machine supposed to be at work or else 

 they tacitly assume a machine at work, but 

 concerning the agents or processes which 

 construct the machine and control its 

 operation they tell us nothing. A machine 

 which runs in a definite orderly way must 

 be constructed according to a definite 

 orderly plan and with the orderly employ- 

 ment of energy, and its operation must be 

 controlled. In short, we must either be- 

 come vitalists and admit the existence of 

 entelechy or some other non-mechanistic 

 principle, or else we must find some sort of 

 dynamic unity and order as the basis of the 

 morphological and physiological unity and 

 order apparent to common observation. 

 "We have been trying to conceive an or- 

 ganic machine ready-made which shall 

 operate in such a way as to satisfy the 

 facts of biological observation and experi- 

 ment. I believe that the essential problem 

 is the problem of the construction and con- 

 trol of the organic machine. If we can 

 gain some insight into the nature of the 

 constructive and controlling processes we 

 shall reach a more adequate conception of 



the individual than if we merely attempt to 

 imagine a ready-made machine or individ- 

 ual which will satisfy the demands of ob- 

 served fact. In other words, an adequate 

 mechanistic theory of the organic individ- 

 ual, if such a theory is possible, must be 

 stated in dynamic terms. It must deal 

 primarily with processes, not structures, 

 and with changes, not with static entities. 



During the last fifteen years I have been 

 chiefly engaged in studying and analyzing 

 experimentally the processes of individua- 

 tion in the lower animals, and this work has 

 led me to certain conclusions concerning 

 the nature of physiological individuality 

 which I wish to present briefly. It has been 

 very generally assumed by biologists that 

 the basis of physiological individuality is 

 inherent in protoplasm and dependent on 

 some sort of self-determined organization. 

 The barrenness of our theories of individ- 

 uality is, I believe, the result of this view. 

 I shall attempt to show that the physiolog- 

 ical individual originates in the final analy- 

 sis, not in a self-determined inherent or- 

 ganization, but in a relation between 

 protoplasm and its environment. There 

 are, of course, many kinds and degrees of 

 individuality in protoplasm, both chemical 

 and physical, such for example as atoms, 

 molecules of the most various degrees of 

 complexity, colloid particles, crystals, me- 

 chanical individuals such as fibrillse result- 

 ing from strain, nuclei, cells, etc., but the 

 integration of any or all of these into a 

 physiological individual with a definite 

 orderly behavior in both space and time 

 can not conceivably be self-determined. 

 We must either accept Driesch's entelechy 

 or some other vitalistic principle or we 

 must seek for the integrating factor in the 

 relation between living protoplasm and its 

 environment. 



In what aspect of this relation can we 

 hope to find such an integrating factor ? I 



