GREEK BIOLOGY AND MEDICINE 



organisms: by the possession of a soul or an 

 organic life with nutritive faculty, a plant is 

 superior to a stone; by the possession of a soul 

 or an organic life, with sensitive, appetitive and 

 motor faculties (besides the nutritive), an 

 animal is superior to a plant; and by the addi- 

 tion of the intellectual faculty in his soul or 

 organic life, man is supreme among animals. 



As another and concomitant test of excel- 

 lence, Aristotle took the amount of vital heat 

 which the animal possessed. " The more per- 

 fect are those which are hotter in their nature 

 and have more moisture and are not earthy in 

 their composition, and the measure of natural 

 heat is the lung when it has blood in it, for 

 generally those animals which have a lung 

 are hotter than those which have it not, and in 

 the former class again those whose lung is not 

 spongy nor solid nor containing only a little 

 blood, but soft and full of blood." '' 



These tests of excellence might be difficult 

 to apply to the classification of animals into 

 genera and species, — a yearning for which with 

 a realization of its practical and logical diffi- 

 culties, pervades Aristotle's biological treatises, 

 as already said. It will be interesting to feel 

 our way along his various avenues of approach 



[46] 



