ON THE FATE OF THE HUMAN EMBRYO IN TUBAL PREGNANCY. 21 



into the lumen. They first form a series of clots around the chorion, fresher clots 

 occur between the older ones, and finally there are delicate streams of uncoagulated 

 blood upon which the ovum is nourished. The trophoblast spreads into long 

 strands between the muscle cells of the tube wall and taps fresh blood sinuses. It 

 spreads in old blood clots along fibrin strands, forming streaks of cells, which often 

 extend several millimeters beyond the tips of the villi. Even the best of specimens 

 frequently show such extensive hemorrhage around the chorion and such marked 

 degeneration of the villi that it is a wonder that the ovum continues to grow nor- 

 mally. In fact, in the majority of cases the hemorrhage has rapidly detached it 

 and it begins to degenerate. It collapses and grows in an irregular fashion, and if 

 the specimen is not aborted into the peritoneal cavity it undergoes further and 

 complete degeneration. Were not these specimens removed by surgeons, I think 

 that in many cases spontaneous healing would occur. In some specimens we find a 

 smaller organized clot with a very few fibrous villi scattered through it. Such a 

 condition must be considered as a tubal pregnancy which has healed spontaneously. 



NORMAL EMBRYOS IN THE UTERUS. 



It is now generally admitted that in normal implantation the ovum penetrates 

 the uterine wall and attaches itself within the mucosa. This fact, which was first 

 established by Count Spee, was subsequently confirmed by Peters and other com- 

 petent investigators. Fairly conclusive evidence was adduced by Brj^ce and 

 Teacher in the careful study of their well-known specimen. When the ovum first 

 reaches the uterus it rapidly penetrates the mucous membrane and forms a cavity 

 for itself by secreting a substance which destroys the cells, the ovum being encir- 

 cled by a layer of dead cells. It may be proper at this point to state that this process 

 of destruction is observed wherever the ovum comes in contact with maternal 

 tissue. The cells undergo a curious hyaline transformation and are converted into 

 a fibrinoid mass often spoken of as fibrin ; but this mass is compact and not inter- 

 mingled with individual cells. It is sometimes spoken of as canalized fibrin. The 

 word "fibrin" in this connection is a misnomer, as was pointed out by Professor 

 Grosser, who constantly speaks of this substance as "fibrinoid." If we add to this 

 the word "necrosis," it seems to me that the term, fibrinoid necrosis would describe 

 the condition as well as our present knowledge warrants. 



The entrance of the ovum into the mucous membrane is accomplished, as a 

 rule, by a profuse local hemorrhage into the cavity which the ovum has burrowed 

 out for itself. This is shown especially well in the specimen by Bryce and Teacher 

 (their Plate III) and in a somewhat older specimen by Peters. As all of these obser- 

 vations were made upon specimens with a questionable history, it is not clearly deter- 

 mined whether the hemorrhage is to be viewed as a normal or as a pathological 

 process. However, it seems to me that this question has been fully set at rest by 

 Herzog, who obtained an ovum with normal implantation from a woman who had 

 died from a puncture wound of the heart. We have here a specimen undoubtedly 

 normal in which the hemorrhage is practically identical with that in Peters's speci- 

 men. Below the point of implantation there are large sinuses of maternal blood 



