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.
