Page:The Works of William Harvey (part 1 of 2).djvu/332

 EXERCISE THE SIXTEENTH.

Second inspection of the egg.

The second day gone by, the circles of the cicatrieula that have been mentioned, have become larger and more conspicuous, and may now be of the size of the nail of the ring-finger, sometimes even of that of the middle finger. By these rings the whole cicatricula is indistinctly divided into two, occa- sionally into three regions, which are frequently of different colours, and bear a strong resemblance to the cornea of the eye, both as respects dimensions, a certain degree of prominence, and the presence of a transparent and limpid fluid included within it. The centre of the cicatricula here stands for the pupil ; but it is occupied with a certain white speck, and ap- pears like the pupil of some small bird's eye obscured by a suffusion or cataract, as it is called. On this account we have called the entire object the oculum ovi, the eye of the egg.

Within the circles of the cicatricula, I say, there is contained a quantity of perfectly bright and transparent fluid, even purer than any crystalline humour ; which, if it be viewed transversely and against the light, the whole spot will rather appear to be situated in the albumen than sunk into the membrane of the yelk, as before : it presents itself as a portion of the albumen dissolved and clarified, and included within a most delicate tunica propria. Hence I entitle this fluid the oculum seu colli- quamentum album ; it is as if a portion of the albumen, lique- fied by the heat, shone apart, (which it does, unless disturbed by being shaken,) and formed a more spirituous and better digested fluid, separated from the rest of the albumen by a tunica propria, and situated between the two masses of liquid, the yelk and the albumen. It differs from the rest of the albumen by its clearness and transparency, as the water of a pellucid spring differs from that of a stagnant pool. The tunic which surrounds this fluid is so fragile and delicate that, unless the egg be handled with great care, it is apt to give way, when the pure spring is rendered turbid by a mixture of fluids.

I was long in doubt what I should conclude as to this