538 



MANUAL OF HISTOLOGY, 



Having now dwelt for a moment on the general anatomy of the ovary, 

 let us commence a more particular consideration of its finer structure with 

 that of the glandular portion. 



Immediately underneath the boundary layer just mentioned is situated 

 a remarkable stratum, almost quite destitute of vessels, which has only 

 recently been recognised. This, which is composed of glandular consti- 

 tuents in process of development, may be called the cortical zone or zone 

 of the primordial follicles. 



Here the essential elements of the organ lie closely crowded in several 

 layers, namely, the young ova (c, d), beautiful globular structures about 

 0*0587 mm. in diameter, consisting of naked granular protoplasm con- 

 taining fatty molecules and a spherical nucleus of about 0'0226 mm. in 

 diameter (fig. 531, 1). 



Each egg-cell, further, is enveloped in a mantle of small nucleated ele- 

 ments. The narrow interposed septa which exist 

 here, forming the stroma of the ovary, are composed 

 of closely-packed fusiform connective-tissue cells, 

 and generally surround each ovum, including its 

 covering of small elements, with a species of special 

 tunic, bounded towards the ovum by a homoge- 

 neous limiting layer or membrana propria. This 

 then constitutes the so-called follicle of the ovary 

 in its earlier form. In this description we have 

 followed the appearances presented in the ovary of 

 the rabbit ; but in the organs of other animals, as, 

 for instance, the dog and cat, a more or less race- 

 mose grouping of the egg-cells is met with fre- 

 quently (fig. 536, c), (Waldei/er). In man and 

 the larger mammals the connective fibrous tissue 

 is more abundant, and the ova more distant one 

 from the other. 



Turning now from this external stratum, with 

 its enormous number of germinal structures, to the 

 more internal portion of the ovary, we find the 

 follicles as we proceed more and more highly deve- 

 loped. Here we encounter some which may have even attained a diameter 

 of 0-0902 or 0'1805 mm. The ovum contained within them is also 

 increased in size, and is enveloped in a distinct membrane (2). The 

 minute cells, situated within the latter and around tire ovum, are also 

 present, but in several layers now, while a system of capillaries may also 

 be observed encircling the follicle with a small number of vessels. In 

 other larger follicles (fig. 530, d), the layers of the smaller elements just 

 mentioned begin to separate from one another, producing a narrow inter- 

 space between the two. 



In the subsequent growth of the follicle this becomes larger and larger, 

 filling at the same time with a watery fluid. 



A follicle at this stage may measure from about 0'3835 to 0'4512 mm. 

 in diameter. On the internal surface of its walls, now supplied by a well- 

 developed capillary network, may be noticed at some one point an enlarged 

 ovum increased to 0*1805 mm. transverse measurement, containing within 

 it a nuclear vesicle of 0'0609 mm. and nucleolus of 0'0135. The tough 

 capsule of the cell is also increased in thickness to 0-0063 mm., and the 

 whole ovum is enclosed within a mass of small cells arranged in layers 



K. 531. Early follicle from 

 the ovary of a rabbit. In 

 1, the ovum is seen with- 

 out the zona pellucidn, a ; 

 in 2, the latter begins to be 

 ay>parent. 



