Boijal Microscopical Society. 47 



from which the villi had been torn, their roots still remaining. 

 This part had evidently been in a more intimate connection with 

 the membrane decidua than the other portions of the surface. Two 

 hours after the abortion, the ovum being carefully freed from the 

 coagulated blood, I opened it, and allowed a part of the very 

 clear serous liquid, contained within, to escape. The first thing 

 which presented itself to view was a small balloon-shaped vesicle 

 (umbilical vesicle ?) of about 6 mm. in breadth by 9 in length, 

 showing numerous, slightly elevated, red spots upon its surface 

 (see Fig. 1 and explanation). An embryo, corresponding to the size 

 of the ovum, such as I had reason to expect, was not to be found. 

 A subsequent examination, however, disclosed that the vesicle was 

 not only connected to the inner surface of the ovum by a small 

 pedicle, but also to a certain opaque mass situated in the wall of the 

 ovum, and which proved to consist of a conglomeration of certain 

 cells and nuclei, to be hereafter described. 



There can remain no doubt that this small mass of cells and 

 nuclei represented the rudimentary embryo, especially as a certain 

 arrangement of these elements, as we shall see hereafter, could not 

 be mistaken, and as furthermore a great number of them were 

 undergoing a process of multiplication. In comparing this accumu- 

 lation of cells, however, with other parts of the ovum, much farther 

 advanced in their histological development, it appeared as if it 

 represented an embryo arrested in its development. Interesting as 

 this phenomenon may be, concerning the science of embryology, I 

 shall nevertheless hesitate to conjecture about it, but confine myself 

 here to the statement, that the woman who aborted the ovum, although 

 not having menstruated for three months, had not felt the usual 

 symptoms of pregnancy but three weeks previous to the abortion. 



In order not to lose the opportunity of examining the tissues in 

 their fresh state, and in their natural hquid, I removed at once a 

 small piece of the wall of the vesicle with a pair of fine scissors, 

 and prepared it for microscopical examination. The latter showed 

 me a great number of coloured blood corpuscles in all stages of 

 development, moving through smaller or larger canals, or issuing 

 from the orifices of the latter which had been produced by the cut 

 of the scissors. This movement, caused by the pressure of the 

 covering glass, as well as by the ensuing issue of a considerable 

 number of blood corpuscles from the cut orifices of the canals, 

 showed me that these latter communicated with each other in the 

 form of a network. An exceedingly fine fibrous tissue could be 

 recognized on their thin transparent walls. In fact, it was only 

 through the movement of the blood corpuscles that I became enabled 

 to discern the canals, in consequence of which it became impossible to 

 study the mutual arrangement of the latter somewhat closer, or 

 to sketch them, for, as soon as a certain portion of the blood had 



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