GREEK BIOLOGY AND MEDICINE 



He drew, nay he drained, his teleology from 

 Aristotle, and, like the Master, applied it to 

 every part of the organic structure: Nature 

 makes nothing without a purpose, and nothing 

 in vain. When Galen is considering the nature 

 and action of an organ, or of the body gen- 

 erally, his mind passes quickly from the sheer 

 description of the thing, and even from the 

 consideration of its efficient cause, and springs 

 forward to grasp its final cause or purpose: 

 therein lies the explanation of the thing, and 

 the explanation, nay the true description, of 

 the function which it is its nature to fulfill. 

 Galen's passionate preoccupation with the 

 purpose of a living organ, colors and even 

 fashions his description both of the organ itself 

 and of the process through which it performs 

 its function. 



The function of the body generally is to 

 afford a setting for the soul or life. The bearer 

 of life, or of the vital forces vivifying the body 

 and directing it to the performance of its 

 functions, is the pneuma. Entering with the 

 breath, it becomes threefold: the psychic 

 pneuma (or, in English, the animal spirits), 

 working in the brain and through the nervous 

 system; the life-pneuma (or vital spirits) of 

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