SECT, i] EMBRYOLOGY IN ANTIQUITY 87 



altered may acquire its appropriate shape and position, its cavities, 

 outgrowths, and attachments, and so forth, it has to undergo a 

 shaping or formative process. One would be justified in calling this 

 substance which undergoes alteration the material of an animal, just 

 as wood is the material of a ship and wax of an image." In this 

 remarkable passage, Galen expresses modern views about chemical 

 growth and chemical differentiation. 



Galen then goes on to treat of embryogeny in more detail. "The 

 seed having been cast into the womb or into the earth — for there is 

 no difference — ", he says (see p. 65), "then after a certain definite 

 period a great number of parts become constituted in the substance 

 which is being generated; these differ as regards moisture, dryness, 

 coldness and warmth, and in all the other qualities which naturally 

 derive therefrom", such as hardness, softness, viscosity, friability, 

 lightness, heaviness, density, rarity, smoothness, roughness, thickness, 

 and thinness. "Now Nature constructs bone, cartilage, nerve, mem- 

 brane, ligament, vein, and so forth at the first stage of the animal's 

 genesis, employing at this task a faculty which is, in general terms, 

 generative and alterative, and, in more detail, warming, chilHng, 

 drying and moistening, or such as spring from the blending of these, 

 for example, the bone-producing, nerve-producing, and cartilage- 

 producing, faculties (since for the sake of clearness these terms must be 

 used as well) .... Now the peculiar flesh of the liver is of a certain kind 

 as well, also that of the spleen, that of the kidneys and that of the 

 lungs, and that of the heart, so also the proper substance of the brain, 

 stomach, oesophagus, intestines and uterus is a sensible element, of 

 similar parts all through, simple and uncompounded. . . . Thus the 

 special alterative faculties in each animal are of the same number 

 as the elementary parts, and further, the activities must necessarily 

 correspond each to one of the special parts, just as each part has its 

 special use. . . . As for the actual substance of the coats of the stomach, 

 intestine, and uterus, each of these has been rendered what it is by 

 a special alterative faculty of nature; while the bringing of these 

 together, the combination therewith of the structures that are in- 

 serted into them, etc. have all been determined by a faculty which 

 we call the shaping or formative faculty; this faculty we also state 

 to be artistic — nay, the best and highest art — doing everything for 

 some purpose, so that there is nothing ineffective or superfluous, or 

 capable of being better disposed." 



