154 THE INDUCIIONS OF BIOLOGY. 



sent no distinctions of parts, and neverttieless feed and 

 grow and move about, Prof. Huxley has remarked that they 

 exhibit Life without Organization. The perpetual changes of 

 form which alone distinguish one of these creatures from an 

 inanimate fragment, are no doubt totally irregular and un- 

 directed. Still they do, through an average of accidents, 

 subserve the creatures' nutrition ; and they do imply an ex- 

 penditure of force that in some way depends on the consump- 

 tion of nutriment. They do, therefore, though in the rudest 

 way, displaya vital adjustment of internal to external relations. 



§ 56. Function falls into divisions of several kinds, ac- 

 cording to our point of view. Let us take these divisions in 

 the order of their simplicity. 



Under Function in its widest sense, are included both the 

 statical and the dynamical distributions of force which an 

 organism opposes to the forces brought to bear on it. In a 

 tree, the woody core of trunk and branches, and in an animal, 

 the skeleton, internal or external, may be regarded as pas- 

 sively resisting the gravity and momentum which tend 

 habitually or occasionally to derange the requisite relations 

 between the organism and its environment ; and since they 

 resist these forces simply by their cohesion, their functions 

 may be classed as statical. Conversely, the leaves and sap- 

 vessels in a tree, and those organs which in an animal 

 similarly carry on nutrition and circulation, as well as those 

 which generate and direct muscular motion, must be con- 

 sidered as dynamical in their actions. From another 

 point of view. Function is divisible into the accumulation of 

 force (latent in food) ; the expenditure of force (latent in the 

 tissues and certain matters absorbed by them) ; and the 

 transfer of force (latent in the prepared nutriment or blood) 

 from the parts which accumulate to the parts which expend. 

 In plants we see little beyond the first of these : expenditure 

 being inappreciable, and transfer required only to facilitate 



