1388

ELEMENTS OF MATERIA MEDICA.

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In the early state of the ovum, the yelk is constituted of a pellucid fluid ly n ’P-’i,, an. 1 *hardly distinguishable from the vesicula cicatriculce. It then becomes i 1

subsequently yellow; globules of oil making their appearance. In a ripe. ® j ts lo»?viscid, tenacious, and of an orange-yellow colour; and lies in the calyx,axis towards the petiolus. It is composed of three layers, the middle onedeepest colour; the inner most enclosing a white fluid called the albumen ce* gtir f»c«substantia alba vitelli), from which passes a little canal to that part of 111of the yelk called the cicatricula.

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The internal surface of the yelk-bag is lined with a very thin stratum °f % ° rform and figure like those of the blood, but arranged organically. The ctca Y^for®'tread (as it is improperly called), is formed by an accumulation of these g' 0 ’^ g { t» eing a mammiform heap, the convexity of which is towards the ce u !ltr toPyelk, and is usually situated nearer the petiolus than the stigma. In t? e t / eT e^ Kis the so-called pellucid pore , which is occupied by a small vesicle n is p® t* 1 .Purkinje (Syrnb. ad ovi avium histor. ante incub. Lipsire, 1830), and called b Jvesicula germinativa , or vesicula cicatricula. It is found in all the ovarian

Fig. 254.

Fig. 255.

Cumulus cicatricula:.

The convex portion faces the yelk.On the top is a small crater, the inneropening of the pore.

Section of the Cicatricula, sthe vesicula in situ.

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s to be a natural organ, since it is found in the ova of fowls which M^j s apP e Sl,s to the male. When the yelk falls into the infundibulum, this vesic , oD tb e ^

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seemsaccess

Tbe Oviduct has some resemblance to a convoluted intestine,side of the animal. Its

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superior expanded free extremity is called the tnjun „ri»■ ,

edges of which are fimbriated. Inferioriy, ^iii®Fig. 256. opens into the cloaca. It is attached ^ aI1 dr“LiJ

the mesometrium. The infundibulum, ore-P, a pes ' r .[.tion of the tube, receives the ovum as it ^ ( b e j ( |ithe calyx of the ovarium. The upper P a ^ ve re<lduct is lined by a fine villous membrane, ^ tb 10 Jfollicles secreting the albumen, or S* a, / e ’(j rs t 1*.^^into a number of longitudinal folds. Tn e i

albumen which the ovum receives forms v» , l | i c * 1 jgJehalazifera of Dutrochet ; at either end o ^^r u t

soft, pellucid,albuminous nodule, which ma ^ e des^'l of

as the rudimentum chalazarum. During deposit?the ovum in the oviduct, it receives re * tat joH s ''LeJalbumen; and, as it undergoes spiral r “ o0) e cUpassage, the above-mentioned processes

Fig. 257.

Yelk, and its Appendages.The spiral chalazae are seen atthe extremities of the yelk;the circular cicatricula in themiddle; and the zona albicansextending from one chalaza tothe other.

Polygonal pieces (crystals?) of Chalk, f ormtn ^meats of the Shell of the b99'

the