LUCEKxN AR1.4: A iS' D THEIR ALLIES. 71 



accepting that view of it. Its whole mass is made up of colorless, minute granular 

 matter shaped into spherical conglomerations which are ])a(ki>d so closely together 

 as to leave no apparent space between them. Tliis is all so transparent as to 

 readily escape casual observation with direct illumination, and one might be led to 

 refer the spheres to the lumen of granules out of the focus of the lens. A careful 

 appliance of the light and the proper adjustments will bring out these features as 

 strongly as we have represented them. There being no smooth, luiiform surface 

 to the yolk, but a scries of irregular, rounded projections, there is no universal, 

 continuous line of contact between it and the vitelline membrane, and consequently 

 the inner surface of the latter stands out sharply and clearly. The diameter of the 

 spherical conglomeration is from one-fourth to one-third that of the germinal 

 vesicle. We are so surprised at this strange structure that we naturally seek to 

 explain it by supposing the spherules to be the granular contents of cells, but that 

 idea we are obliged to resign, for after the most careful search we have failed to 

 detect the faintest trace of a wall about the globules. 



142. The germinative vesicle {(jv) is not much less than one-half the shorter 

 diameter of the egg. In shape it varies from spherical to broadly oval or spheroidal, 

 perhaps owing to the mutual pressure of the eggs. It is perfectly clear, and free 

 from granules, and contains a large macula or vesicula Wiigncri {wv^. The contents 

 of the latter are even less refractive than that of the germinal vesicle, and both 

 are so in a very low degree. Tlie wall of the germinal vesicle is excessively thin, 

 appearing like a mere film under a magnifying power of five hundred diameters, 

 and consequently its contents seem to be in a hollow space excavated in the side 

 of the yolk. 



143. The Egg is an organized heiag. — There is here, in the singular relations 

 and form of the constituents of the yolk, in its stability and evidently organized 

 condition, the very reverse of an unstable, simply fluid state. We have for a 

 number of years argued that the yolk of the egg of all animals is not a homogeneous, 

 homomorphous, mere fluid contents of a sac, stored as if iu a reservoir for future 

 elaboration, but, on the contrary, is an organized aggregation of matter under the 

 influence of certain forces of a vital nature, which direct the laying down of its 

 parts in definite places and in certain forms, always retaining them tlu;re from 

 the very beginning of the development of the e^^. Embryologists have frequently 

 noted the precision and systematic order with which the contents of an egg are dis- 

 posed, but they have invariably failed to recognize the organized character of the 

 different regions and their distinct relations to each other, and to the changes Avhich 

 are to take place in the future. We need but refer to the eggs of birds to prove 

 that the ovum is so far organized as to be inherently self-sustaining, existing in a 

 low state of vitality for a comparatively indefinite length of time, waiting for the 

 coming of such circumstances — either belonging to the parent or arising from 

 purely physical sources — as shall cause it to develop to a higher phase. 



We are well aware of the fact that some embryologists claim that the embryo 

 always develops in the region where the germinal vesicle lies, and that the yolk is 

 drawTr into the body as if it were a mere supply of crude nourishment, but we do 

 not know that any one but ourselves has promulgated the idea that the germinal . 



