FUNCTION. 199 



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

 being comparatively slight, and transfer required mainly to 

 facilitate accumulation. In animals the function of accumu- 

 lation comprehends those processes by which the materials 

 containing latent energy are taken in, digested, and separated 

 from other materials; the function of transfer comprehends 

 those processes by which these materials, and such others as 

 are needful to liberate the energies they contain, are con- 

 veyed throughout the organism ; and the function of expendi- 

 ture comprehends those processes by which the energy is 

 liberated from these materials and transformed into properly 

 co-ordinated motions. Each of these three most gene- 



ral divisions includes several more special divisions. The 

 accumulation of energy may be separated into alimentation 

 and aeration; of which the first is again separable into the 

 various acts gone through between prehension of food and 

 the transformation of part of it into blood. By the transfer 

 of energy is to be understood what we call circulation; if the 

 meaning of circulation be extended to embrace the duties of 

 both the vascular system and the lymphatics. Under the 

 head of expenditure of energy come nervous actions and 

 muscular actions: though not absolutely co-extensive with 

 expenditure these are almost so. Lastly, there are the 

 subsidiary functions which do not properly fall within any 

 of these general tunctions, but subserve them by removing 

 the obstacles to their performance: those, namely, of ex- 

 cretion and exhalation, whereby waste products are got 

 rid of. Again, disregarding their purposes and 



considering them analytically, the general physiologist may 

 consider functions in their widest sense as the correlatives of 

 tissues — the actions of epidermic tissue, cartilaginous tissue, 

 elastic tissue, connective tissue, osseous tissue, muscular 

 tissue, nervous tissue, glandular tissue. Once more, 



physiology in its concrete interpretations recognizes special 

 functions as the ends of special organs — regards the teeth as 

 having the office of mastication; the heart as an apparatus 

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