ON THE FATE OF THE HUMAN EMBRYO IN TUBAL PREGNANCY. 55 



cavity, it becomes larger and larger; it is encircled by a dense fibrous clot and dis- 

 integrates. Often the entire tube wall, which is thin and inflamed, has practically 

 disappeared. 



I have intentionally not taken up the question of the nature of the inflammation 

 which appears about a tubal pregnancy. It seems, however, that in certain 

 instances this inflammation is due to the tightening up of an old infection that had 

 occurred at the time of a previous labor, although the evidence points more towards 

 venereal disease as a more usual etiological factor. The more frequent incidence 

 of tubal pregnancy in cities than in country districts and the frequent histories of 

 gonorrhea in these cases point stiongly towards the latter as the chief cause of tubal 

 pregnancy. I do not believe that the evidence we have now warrants a more 

 definite statement than this, as the subject can not be determined by the histological 

 picture. For the present, therefore, the question must still remain open. 



NORMAL IMPLANTATION. 



In case the ovum becomes well implanted within the middle of the tube and 

 ruptures into the broad ligament, conditions are brought about which favor the 

 development of a normal embryo. Rupture on the free side of the tube would 

 throw the embryo into the peritoneal cavity and therefore would probably terminate 

 its life. The same is true when the implantation takes place near the uterus. Here 

 the tube distends with difficulty. The ovum burrows into its thick wall and usually 

 passes right through into the peritoneal cavity. We have numerous beautiful 

 specimens illustrating this point. 



Table 1, given on page 5 of this article, is arranged in three columns, each 

 column being divided into two, marked "Examined" and "Unexamined," respect- 

 ively. The specimens have been arranged in this way to facilitate the study of 

 them statistically. When embryological specimens were first sent me only normal 

 ones from tubal pregnancies were included, and this accounts for the large number 

 of specimens in the first 500 of this collection containing normal embryos. For 

 statistical purposes, only the columns marked "Unexamined" should be compared. 

 In these cases the specimens were not selected by the surgeons who performed 

 the operations, so that during a period of 17 years, since No. 109 was sent me, I have 

 obtained 13 normal embryos, 20 pathological embryos, and 47 pathological ova, 

 among 80 unexamined tubal pregnancies. Thus it will be seen that of the preg- 

 nancies which were not examined before the specimens were sent to this collection, 

 16 per cent, or nearly one-sixth of the whole number, contained normal embryos. 

 I am rather of the opinion that this is too large a proportion, inasmuch as the 

 small tubes containing a small ovum were generally not sent to us. 



It seems highly probable that, when the ovum is normally implanted and con- 

 tains a normal embryo, it is attached to the tube wall much as the ovum is attached 

 to the uterus normally. It burrows through the mucous membrane and makes for 

 itself a space between it and the muscular wall. This process is accompanied by a 

 marked hemorrhage probably much more pronounced than is usually the case for 

 a uterine implantation. The trophoblast promptly attacks the venous sinuses of 



