ENVIRONMENTAL CONDITIONS 3 



it as manifested by alterations in the performance of function of 

 the series (See correlations). 



It is to be said that the morphological and physiological per- 

 formances of the complex protoplasmic machine may be moder- 

 ated, or totally suppressed by the action of incident forces, and 

 latent capacities may be called into action, but such variation in 

 external conditions may not originate processes, or set up action 

 of a new kind, except by long continued influence of such force 

 upon a great number of masses of living matter standing in a 

 linear relation to each other. This inertia, or essential character- 

 istic, of protoplasm is incapable of chemical or physical analysis, 

 and the organism has acquired properties other than those due 

 simply to its physical and chemical composition. 



3. Environmental Conditions. The performance of the col- 

 lective functions of living matter depends upon, or is influenced 

 by, the presence of certain external conditions or trophic forces, 

 such as temperature, light, electricity, moisture, and chemical 

 composition of the surrounding medium or substratum. To these 

 forces protoplasm sustains a double relationship. 



First it is to be said that each of the necessary trophic environ- 

 mental conditions must be present, in a certain proportion, or in- 

 tensity, in order to give rise to, or to allow, the full molecular ac- 

 tivity of the constituents, and the manifestations constituting the 

 phenomena of the full cycle of life. Thus a certain amount of 

 moisture is necessary to dissolve and dilute the crystalloids and 

 soluble colloids in order that the peculiar forms of activity neces- 

 sary for growth, respiration and metabolism in general may be 

 carried on, while a certain degree of temperature is also a pre- 

 requisite for the characteristic molecular motion on which these 

 phenomena are based. This connection of external forces with 

 protoplasm may be designated as the tonic relation. Unfavorable 

 intensity or concentration of any of the incident forces may in- 

 hibit the functions, singly or in groups, until but a residuum of 

 activity is shown, while total suppression or undue increase of any 

 force may bring the whole mechanism to a standstill, or state of 



