98 EMBRYOLOGY FROM GALEN [pt. ii 



are sufficiently confused and repetitive, does yet succeed in infusing 

 a clarity and incisiveness into his style. Albert, on the other hand, 

 allows his argument to wander through his twenty-six books De 

 Animalibus in the most complex convolutions, so that the sections on 

 generation and embryology are found indiscriminately in the first, 

 sixth, ninth, fifteenth, sixteenth, and seventeenth. In Book i he gives 

 a kind of summary or skeleton of his views on the embryo. These 

 follow Aristotle fairly closely; thus, he accepts the AristoteHan classi- 

 fication of animals according to their manner of generation, and 

 thinks still that caterpillars are immature eggs ; he derives the embryo 

 from the white, not the yolk, and he explains why soft-shelled eggs, 

 being imperfect, are of one colour only. But there are new observa- 

 tions; for instance, he describes an ovum in ovo, which he has seen, 

 calling it a natura peccatis, and he speaks definitely of the seed of 

 the woman, thus departing from Peripatetic opinion, and adopting 

 the Epicurean view. The female seed, he thinks, suflfers coagulation 

 like cheese by the male seed, and to these two humidities there must 

 be added a third, namely, the menstrual blood (corresponding to 

 the yolk in the case of the bird). "When these three humidities 

 therefore have been brought into one place, all the similar members 

 except the blood and fat are formed from the two humidities of which 

 one generates actively but the other passively. But the blood which is 

 attracted for the nutriment of the embryo is double in virtue and 

 double in substance. For a certain part of the blood is united with 

 the sperm in such a way that it takes on some of the virtue of the 

 seed because a certain part of the spermatic humour remains in it 

 and from this are begotten the teeth and for this reason they grow 

 again if they are pulled out at an age near the time of sperm-making 

 and do not grow again at an age remoter from this, at which the 

 virtue of the first generating principle has vanished from the blood. 

 But another part of the blood is of twofold or threefold substance 

 and from the thick part of the blood itself is generated the flesh. 

 And this flows in and flows out and grows again if rubbed away. 

 From the watery part of the same blood or of the nutritive humour 

 are generated the fat and oil and this flows in and out more easily 

 than the flesh itself, but other parts of the blood are its refuse and 

 impurities and are not attracted to the generation of any part of the 

 animal, but having been collected until birth are expelled with the 

 embryo from the uterus in the foetal membranes, like the remnants 



