350 COSMIC PHILOSOPHY. [ft. n. 



local pressure of the tissues. But in a highly-evolved 

 animal, which possesses a well-developed vascular system, 

 the blood runs in definite channels, and with well-marked 

 differences of movement. Its movement is slow and con- 

 tinuous in the capillaries, fast and continuous in the veins, 

 still faster but discontinuous in the arteries ; while the 

 rhythms in all are subordinated by the central rhythm of 

 the heart. Still more remarkable, in the most complex 

 organisms, is that kind of functional integration which 

 consists in the mutual dependence of different functions. 

 Neither alimentation nor circulation nor respiration can go 

 on alone ; and all three are dependent upon the continuance 

 of nervous action, which in turn depends alike upon each of 

 the three. A few whiffs of tobacco, for example, setting up 

 slight molecular changes in the medulla oblongata, increase 

 the heart's rate of pulsation, and stimulate every one of the 

 alimentary secretions, while it is probable also that, through 

 the medium of the sympathetic ganglia, the sectional area 

 of every artery is slightly altered. The cautious physician, 

 in prescribing a powerful drug, knows that he is dealing with 

 an integration of motions so extensive that the disturbance 

 of any one will alter the directions and composition of all 

 the others to a degree which baffles accurate calculation. 

 Contrasting with such cases as these the homogeneous, inde- 

 finite and uncombined movements of those lowest animals, 

 that are borne hither and thither by the vibrations of cilia, 

 it becomes evident that the formula which expresses the 

 structural evolution of matter, expresses also the functional 

 evolution of the motion which the integrating matter 

 retains. 



Embracing now in one general view the various kinds of 

 transformation exemplified in the present chapter, we find 

 that our survey of organic development completely justifies 

 Mr. Spencer's technical statement : — " Evolution is an inte- 

 gration of matter and concomitant dissipation of motion, 



