450 ON GENERATION. 



Further, on the preceding view of Fabricius it would fol- 

 low that the heart, lungs, liver, spleen, &c., were not spermatic 

 parts, did not originate from the seed (which he, however, will 

 by no means allow), inasmuch as they too are by and by nou- 

 rished by the blood and grow out of it ; for every part is both 

 formed and nourished by the same means, and nutrition is 

 nothing more than the substitution of a like matter in the 

 room of that which is lost. 



Nor would he find less difficulty in answering the question 

 how it happens that when the albumen in the egg is all con- 

 sumed, the cold and white parts, such as the bones, ligaments, 

 brain, spinal marrow, &c., continue to be nourished and to 

 grow by means of the vitellus ? which to these must be nou- 

 rishment as inappropriate as albumen to the hot, red, and san- 

 guine parts. 



Adopting the views commented on, indeed, we should be 

 compelled to admit that the hot and sanguineous parts were 

 the last to be produced : the flesh after the bones ; the liver, 

 spleen, and lungs after the ligaments and intestinal canal ; and 

 further, that the cold parts of the chick must come together 

 and attain maturity, the white being all the while consumed, 

 and the hot parts be engendered subsequently, when the vitel- 

 lus fails and ceases from nourishing them ; and then it would be 

 certain that all the parts could not take their rise in and be 

 constituted out of the same clear liquid. All such conclusions, 

 however, are refuted by simple ocular inspection. 



I add another argument to those already supplied : the eggs 

 of cartilaginous fishes skates, the dog-fish, &c., are of two 

 colours their yelks are of a good deep colour ; nevertheless all 

 the parts of these fishes are white, bloodless, and cold, not 

 even excepting the substance of their liver. On the contrary, 

 I have seen a certain breed of fowls of large size, their feathers 

 black, their flesh well supplied with blood, their liver red ; yet 

 were the yelks of the eggs of these fowls fruitful eggs 

 of the palest shade of yellow, not deeper than the tint of ripe 

 barley straw. 



Fabricius, however, seems in these words 1 to retract all he 

 has but just said : " There is one thing to be particularly 



1 Op. cit. p. 55. 



