14 HUMAN MAGMA RftTICULft IN NORMAI, AND PATHOLOGICAL DEVELOPMENT. 



and the adjacent chorionic wall where the fibrils arc unusually abundant. This 

 specimen was obtained from a liysterectoni.\- upon a woman, 25 years old, for a 

 fibrous tumor of the uterus. She had been married 4 years, this being her first 

 ])re<inancy. There were no sjiecial symptoms bearing upon the case, excejiting the 

 discomfort which accompanied the tumor of the uterus. Her last menstrual period 

 had been delayed, and as it had been more profuse than usual she believed that she 

 had had a miscarriage; otherwise, everything appeared normal. This was con- 

 firmed by a careful examination of the si)ecimen, which showed it to be normal in 

 every resjiect. The uterus was opened by the surgeon at the time of the o})eration, 

 but fortunately the site of the ovum was not injured. The specimen was sent to 

 the laboratorj' immediately, where it was fixed by Dr. Evans, who made the fol- 

 lowing record : 



"The .specimen consists of a myomatous uterus which has been opened (apparently in a midline 

 anterior incision) so as to disclose an abundant deciduous endometrium thrown into large folds. 

 At the upper posterior surface of the uterus an oval mass, about 2.5 \>y 20 by 20 nun., projects. It is a 

 sac and is covered with a rather smooth moml)rane (dcM'idua reflexa), beneath whicli tortuous vessels 

 are apparent. On one side the sac (tiie implanted chorion) is adherent to tlic uterine mucosa 

 (decidua vera). With a sharp scalpel the entire mass was dissected away from the uterus and brouglit 

 under a binocular microscope in warm salt solution. The middle portion of the free surface was oiK-ned 

 carefully, beautiful \illi iicinfi foiuid, and then the delicate wall of the chorion was divided. Within, 

 a transparent young embryo and its unibilical vesicle were seen, the embrj'o apjiearing to i)e about 

 5 mm. in length. Through this opening in the chorion, warm (40° C.) saturated aqueous solution of 

 HgClo, containing 5 per cent glacial acetic acid, was gently introduced and the entire mass placed in 

 500 c.c. of this fi.xaf ion fluid. The main body of tlu> uterus was dissected from the myomatous nodule 

 and fixed in 10 per cent formalin, the site of the implanted ovum being mtirked bya short wooden rod." 



The fixed and hardened spccimini had undergone a readily appreciable shrinkage 

 from the condition seen in warm salt solution. All of the tissues were beautifully 

 preserved. The implanted ovum, covered wath the decidua capsularis, measures 

 approximately 22 by 18 by 11 mm. The adjacent decidua parietalis is thrown into 

 large folds, which are themselves marked b}' numerous tiny elongated crack-like 

 depressions, as well as by more circular pit-like apertures. The relatively smooth 

 l)ut irregular surface of the decidua capsularis is marked here and there by very 

 conspicuous, small, oval pits, which may attain 0.5 mm. in diameter. The four 

 flaps of this coat at its highest point, where it was opened directly over the middle 

 of the ovum, are rather smooth on their inner surface and stand apart from the 

 subjacent chorionic villi (intervillous space) to which they were originally adherent. 

 The villi are about 2.5 mm. in length and possess one or two large branches and 

 many "stub-like" tiny bullions ones on the main stem. The villi are uniformly- 

 distributed in the small area expo.sed. With a slender scalpel the ovum was care- 

 fully divided under the dissecting micro.scope, the embryo and yolk-.sac being visible. 

 The yolk-sac appears to be almost 2 cm. in diameter and the embryo is surrounded 

 by its amnion, its head (visible from above) being about 3 cm. in length and showing 

 the fourth ventricle covered by a transparent ependyma. Two gill-arches are 

 visible. The yolk-sac surface presents an exqui.site picture of irregular, clear va.s- 

 cular channels and a uniform pattern of small, opaque, white blood-islands. The 

 preservation seems perfect. 



