HUMAN MAGMA RETICULE IN NORMAL AND PATHOLOGICAL DEVELOPMENT. 13 



normal villi and contains a well-formed embryo within the amnion. It is apparently 

 normal in every respect. No magma could be seen at the time, Ijut drawings of 

 the embryo subsequently made show delicate strands of fibrils forming a fuzzy 

 layer around the umbilical cord and extending over the umbilical vesicle; undoubt- 

 edly these are magma fibrils. This seems to be the normal condition for this stage 

 and is verified in specimen No. 836, to be described later. Sections through the 

 mass and the chorion, stained with carmine, show the magma as a granular mass; 

 only at points is there any indication of fibrils. However, this mass resolves itself 

 into the most definite fibrils when colored with Van Gieson stain, in Mallory's 

 stain, in hematoxylin, aurantia and orange G., or in iron hematoxylin. With Van 

 Gieson stain the fibrils take on fuchsin color about as intenselj^ as do the fibrils of 

 the chorionic wall, with which they are continuous. The contrast obtained with 

 jVIallory 's stain is quite marked, as the endoplasm of the mesenchyme of the chorionic 

 wall stains slightly blue, while the exoplasm and the fibrils of the magma reticule 

 remain unstained. This difference is not shown in sections stained in iron hema- 

 toxylin, as all fibrils are colored intensely black. However, it does not come out 

 with the Oppels-Biondi method or with hematoxylin and eosin or aurantia. As 

 the fibrils of the magma are continuous with those of the exoplasm of the chorionic 

 wall, which do not stain in Mallory's connective-tissue mixture, they can not be 

 considered as white fibers, and from their failure to stain in Weigert's elastic-tissue 

 mixture they are not elastic. As will be shown subsequently, they give the reactions 

 of embryonic connective-tissue syncytium; and this is Retzius's opinion regarding 

 their character. In specimen No. 486 the fibrils of the magma are not accompanied 

 by any nuclei; so they must be viewed as belonging to the cells of the chorionic wall, 

 from which they extend to bind the chorion with the primordium of the embryo. 



Specimen No. 588 came from a woman who had 2 children living, aged 14 and 

 20 years respectively. Since the last birth she had aborted 11 times, and in the 

 opinion of her phj'sician all the abortions were due to mechanical means. This 

 indicates that the specimen is normal. A figure of this embryo with strands of 

 magma radiating from the umbilical cord and vesicle is shown in plate 3, figure 2. 



Specimen No. 136 is of about the same stage of development as No. 588, 

 although the chorion is covered with poorly defined villi. For an embryo of this 

 stage it is unusually small, and I have therefore listed it with the pathological 

 specimens in my paper on monsters. A photograph of the ovum after it had been 

 cut open shows that the chorion is completely filled with reticular magma, so that 

 the embryo is practically obscured. A block of the whole ovum encircling the 

 embryo was cut in serial sections. These show that there are strands of tissue 

 accompanied by cells which form partitions in the exoccelom. The quantity of the 

 magma appears to be somewhat excessive for a normal ovum of this stage of 

 development. 



No. 836, a perfect specimen containing an embrj'o 4 mm. in length, settles 

 definitely the condition of the magma at this stage of development (plate 1, figures 

 3 and 4). In this ovum the exoccelom, measuring 9 by 4 mm., contains a delicate 

 spiderweb-like reticular magma, several of the strands being considerably larger 

 than the others. Most of this magma occurs between the yolk-sac and the amnion 



