i84 EMBRYOLOGY IN THE SEVENTEENTH [pt. ii 



no spirit is given off. If egg-white is applied to the naked eye or naked 

 nerve it does not give the smallest sense of pain, and scarcely affects the 

 smell; nothing more inert and more insipid can be put on the tongue. It 

 appears mucous and viscid to the touch, not at all penetrable. Hence in 

 the fresh white of an egg there is no alkali or acid, or both together. It is 

 indeed a thick, sticky, inert, and insipid liquor, yet from this truly vital 

 liquid at a heat of 93 degrees within the space of 2 1 days the chick grows 

 in the incubated egg from a tiny mass hardly weighing a hundredth of a 

 grain into the perfect body of an animal, weighing an ounce or more. 

 We have learnt therefore of a liquid distinct from all others, from which by 

 inscrutable causes fibres, membranes, vessels, entrails, muscles, bones, 

 cartilages, and all the other parts, tendons, ligaments, the beak, the claws, 

 the feathers, and all the humours can be produced — and yet in this liquid 

 we find softness, inertia, absence of acid, alkali, and spirit, and no ten- 

 dency to effervesce. Indeed, if there were the slightest effervescence in it, 

 it would certainly break the eggshell, therefore we see from how slow and 

 inactive a mass all the solid and fluid parts of the chick are constructed. 

 And yet this itself is rendered absolutely useless for forming the chick by 

 greater heat. It scarcely bears 100 degrees with good effect but at a less 

 temperature never brings forth a chick, for under 80 degrees will not 

 suffice. But by a heat kept between these limits, there is brought about so 

 marvellous an attenuation of the mucous inactivity that it can exhale a 

 great part through the shell of the egg and the two membranes, the yolk 

 and chalazae alone remaining along with the amniotic sac. For the yolk, 

 the uterine placenta of the chick, takes little part in the nourishment. 

 Meanwhile Malpighius has shown that this albumen is not a liquid of a 

 homogeneous kind, as the blood-serum flowing through the vital vessels 

 is, but that it is a structure composed of numerous membrane-like and 

 distinct small saccules, filled with a liquid of their own, in the same way 

 as in the vitreous humour of the eye. 



[Processus 1 1 1 .] Exploration of the egg-white with alcohol. In this trans- 

 parent vessel is the albumen of an egg, and into it, as you perceive, I 

 gently pour the purest alcohol, so that it descends down the sides of the 

 vessel and reaches the albumen. I do this deliberately and with such 

 solicitude that you may see the surface of the albumen which, touching 

 the alcohol, holds it up, being immediately coagulated, while the lower 

 part remains liquid and transparent. As I now gently shake them together, 

 it appears evident that wherever the alcohol touches the albumen a con- 

 cretion is formed. Behold now, while I shake them up thoroughly together, 

 all the egg-white is coagulated. If alcohol previously warmed is employed 

 in this experiment, the same result is brought about but more rapidly. 

 It appears therefore that the purest vegetable spirits immediately coagulate 

 the plastic and nutrient material. 



[Processus 112.] The fresh albumen of an egg is broken up by distillation. 

 These fresh eggs have been cooked in pure water till they became hard. 

 I now take the shining white, separating off all the other things, and break 

 it up into small pieces. I put these, as you see, into a clean glass retort 



