Ton ephexês logon hapanta poiêsometha zêtountes hyper hôn ex archês prouthemetha, posai te kai tines eisin hai tês physeôs dynameis kai ti poiein ergon hekastê pephyken. ergon de dêlonoti kalô to gegonos êdê kai sympeplê||rômenon hypo tês energeias autôn, hoion to 7 haima, tên sarka, to neuron; energeian de tên drastikên onomazô kinêsin kai tên tautês aitian dynamin. epei gar en tô to sition haima gignesthai pathêtikê men hê tou sitiou, drastikê d' hê tês phlebos gignetai kinêsis, hôsautôs de kan tô metapherein ta kôla kinei men ho mys, kineitai de ta osta, tên men tês phlebos kai tôn myôn kinêsin energeian einai phêmi, tên de tôn sitiôn te kai tôn ostôn symptôma te kai pathêma; ta men gar alloioutai, ta de pheretai. tên men oun energeian enchôrei kalein kai ergon tês physeôs, hoion tên pepsin, tên anadosin, tên haimatôsin, ou mên to g' ergon ex hapantos energeian; hê gar toi sarx ergon men esti tês physeôs, ou mên energeia ge. dêlon oun, hôs thateron men tôn onomatôn dichôs legetai, thateron d' ou. III It appears to me, then, that the vein, as well as each of the other parts, functions in such and such a way according to the manner in which _the four qualities_[27] are mixed. There are, however, a considerable number of not undistinguished men--philosophers and physicians--who refer action to the Warm and the Cold, and who subordinate to these, as passive, the Dry and the Moist; Aristotle, in fact, was the first who attempted to bring back the causes of the various special activities to these principles, and he was followed later by the Stoic school. These latter, of course, could logically make active principles of the Warm and Cold, since they refer the change of the elements themselves into one another to certain _diffusions_ and _condensations_.[28] This does not hold of Aristotle, however; seeing that he employed the four qualities to explain the genesis of the elements, he ought properly to have also referred the causes of all the special activities to these. How is it that he uses the four qualities in his book "On Genesis and Destruction," whilst in his "Meteorology," his "Problems," and many other works he uses the two only? Of course, if anyone were to maintain that in the case of animals and plants the Warm and Cold are _more_ active, the Dry and Moist _less_ so, he might perhaps have even Hippocrates on his side; but if he were to say that this happens in all cases, he would, I imagine, lack support, not merely from Hippocrates, but even from Aristotle himself--if, at least, Aristotle chose to remember what he himself taught us in his work "On Genesis and Destruction," not as a matter of simple statement, but with an accompanying demonstration. I have, however, also investigated these questions, in so far as they are of value to a physician, in my work "On Temperaments." III