THE SCOPE OF BIOLOGY. 95 



ganism is affected, then if A produces in the organism some 

 change a, there follows in the organism some change b, fitted 

 in time, direction, and amount to meet the action B — a 

 change which is often required to be much larger than its 

 antecedent. Mark, now, the relation between these 



two final results. On the one hand, for the maintenance of 

 that correspondence between inner and outer actions which 

 constitutes Life, an organism must be susceptible to small 

 changes from small external forces (as in sensation), and must 

 be able to initiate large changes in opposition to large external 

 forces (as in muscular action). On the other hand, organic 

 matter is at once extremely sensitive to disturbing agencies 

 of all kinds, and is capable of suddenly evolving motion in 

 great amounts. That is to say, the constitution of organic 

 matter specially adapts it to receive and produce the internal 

 changes required to balance external changes. 



This being the general character of the vital Functions, 

 and of the Matter in which they are performed, the science 

 of Biology becomes an account of all the phenomena attend- 

 ant on the performance of such Functions by such Matter — 

 an account of all the conditions, concomitants, and conse- 

 quences, under the various circumstances fallen into by living 

 bodies. If all the functional phenomena which living bodies 

 present, are, as we have concluded, incidents in the main- 

 tenance of a correspondence between inner and outer ac- 

 tions ; and if all the structural phenomena which living 

 bodies present, are direct or indirect concomitants of func- 

 tional phenomena ; then the entire Science of Life, must con- 

 sist in a detailed interpretation of all these functional and 

 structural phenomena in their relations to the phenomena of 

 the environment. Immediately or mediately, proximately 

 or remotely, every trait exhibited by organic bodies, as 

 distinguished from inorganic bodies, must be referable to 

 this continuous adjustment between their actions and the 

 actions going on around them. Such being the extent and 

 nature of our subject-matter, it may be thus divided. 



