Cuap. I. ORIGIN OF THE EGG. 453 
i, 5, 9); yet the thinnest portions are preferable, because of the greater homo- 
geneity of the transmitted light. 
It is beyond the reach of pen or pencil to illustrate satisfactorily the unmis- 
takable physiognomy of the ovarian egg at that age, when it is smaller than the 
cells of the Graffian body which surround it. The task becomes more diffi- 
cult still when the very natural question arises, How is it known that these 
peculiar forms are eggs? The most direct answer to this question is, by compar- 
ison, which is in fact at the base of all inductive reasonnmg. But the argument 
here is not to be one of words alone; for every step of the induction shall be 
illustrated by examples drawn from nature, and words will serve merely to point 
out their true character. 
No one will deny that the most correct and philosophical method is that which 
follows the development of the life of the eggs, seizing upon and watching the 
changes and growth of the minutest cells till that period when, by their contents 
and acknowledged characteristics, they are recognized without reserve to be eggs; 
although, in an argument upon the identity of an unknown with a known body, 
our finite senses usually prefer to start from the latter, and proceed toward the 
former by a series of reductions, tracing embryonic life just as it sometimes appar- 
ently develops itself in a series of retrograde metamorphoses. Yet, although we 
have in a few rare cases seeming examples of this kind, it is, to a mind so 
deeply imbued with the phenomena of the whole course of development as to 
follow instinctively in the path of nature, a foreed and unnatural mode of inter- 
pretation of the phases peculiar to the several successive stages of the genesis of 
the ovarian egg. 
Upon submitting the ovary to the microscope, with a magnifying power of 
about five hundred diameters, there may be observed in the field, scattered 
among the larger eggs, quite a number of smaller ones, varying from mere 
granular, minute, dark specks (PI. 8, fig. 1, a) to a size about four times the diam- 
eter of the cells of the corpus graffianum which inclose them (PI. 8, fig. 1, dy). 
These eges have all one common physiognomy, which at once impels a belief that 
they are so many different grades in the development of one kind of cells, pecu- 
liar in themselves, and very different from the mass of hyaline and colorless cells of 
unvarying size about them. The thick, dark outline, the peculiarly brilliant- and 
strongly refractive, homogeneous yellowish contents, and the lateral nucleus,’ when 
present, are entirely different from the thin walls, transparent, irrefractive contents, 
and central nucleus of the neighboring cells of the corpus graffianum (PI. 8, fig. 
» 1 The conflicting views entertained by anatomists changes necessary in the nomenclature of the cell, its 
upon the formation of cells have rendered some envelope and contents, which are discussed below. 
