82 RALPH S. LILLI'E. 



involves not only a chemical synthesis, but also a morphological 

 synthesis, i. e., a rebuilding of organized structure. The con- 

 structive and the destructive processes are inseparable; syn- 

 thesis is life, whether during rest or activity. Hence the rate of 

 construction must be regarded as ultimately under the same kind 

 of control as the rate of destruction, even though the latter is 

 more obviously subject to modification under the usual condi- 

 tions of life (as in stimulation, voluntary action, etc.). 1 'As 

 instances of the initiation of organic construction by conditions 

 whose primary effect is to stimulate, i. e., to increase the energy- 

 yielding dissimilation, Bernard cites the awakening of dormant 

 germs or hibernating animals by rise of temperature or other 

 stimulating condition; 2 the resumption of growth and other pro- 

 cesses involving increased assimilation illustrates the constant, 

 though it may be indirect, nature of the interconnection. An 

 apposite present day-illustration of the same phenomenon would 

 be the initiation of development in unfertilized eggs by a tem- 

 porary cytolytic action. But one does not need to search for 

 instances; the reciprocal interdependence of assimilation and 

 dissimilation is seen everywhere in organisms; how essential this 

 relation is for the preservation of life appears, for example, in the 

 general fact that in all animals increased muscular or other 

 activity hastens the onset of hunger, i. e., of the condition neces- 

 sary for supplying the raw material for construction. The 

 maintenance of a balance between the two kinds of metabolic 

 processes constitutes probably the most fundamental of the 

 various types of organic regulation. 



There is no doubt that a general regulatory condition of this 

 kind exists in all organisms; the problem is to determine the 

 essential physico-chemical conditions upon which it depends. 

 We must regard the living system primarily as one in which the 

 synthesis of both chemical substance and organized structure is 

 controlled by functional activity. And during the growth and 

 development of the system, i. e., at the periods when synthetic 



1 Bernard gives direct experimental evidence of the identity of the conditions 

 controlling growth with those controlling stimulation by showing that growth 

 (e. g. in seedlings) may be anaesthetized under the same conditions as the different 

 forms of irritability. Cf. his chapter on Irritability, Lecons, Vol i, p. 267. 



2 Cf. Lemons, Vol. i, Chapter 2, p. no. 



