DEPARTMENT OF EMBRYOLOGY. 113 



The following papers have been published. 



Publication No. 221: 



No. 1. Mall, Franklin P. On the fate of the human embrj'o in tubal pregnancy. 

 Publication No. 222: 



No. 2. Watt, James C. Description of young twin human embryos with 17-19 paired 



somites. 

 No. 3. Clark, Eliot R. An anomaly of the thoracic duct withabearing on the embryology 



of the lymphatic system. 

 No. 4. Meyer, A. W. Fields, graphs, and other data on fetal growth. 

 No. 5. Comer, George W. The corpus luteiun of pregnancy as it is in swine. 

 No. 6. Essick, Charles R. Transitory cavities in the corpus striatum of the human 



embryos. 

 Publication No. 228: 



No. 7. Sabin, Florence R. On the fate of the posterior cardinal veins and their relation to 



the development of the vena cava and azygos in the embryo pig. 

 No. 8. Duesberg, Jules. Recherches cytologiques sur la f^condation des ascidiens et sur 



leur d6veloppement. 

 No. 9. Shipley, Paul G., and George B. Wislocki. The histology of the poison-glands of 



Bufo agim and its bearing upon the formation of epinephrin within the glands. 



The plan is to publish in the Contributions those papers from the 

 Department or in relation to the Department which on account of their 

 extent and the character of their illustrations can not be published in 

 technical journals. 



The first paper of this series is by myself, on the fate of the human 

 ovum in tubal pregnancy. The material for this study includes 146 

 specimens which have been collected by about 100 physicians in various 

 parts of the United States and in Asia during the past eighteen years. 

 This work lagged until it received support from the Carnegie Institu- 

 tion of Washington, and I am pleased to present it as the first paper 

 appearing in the Contributions from the newly established Department 

 of Embryology. The scope of the work is not only embryological, 

 but also etiological — i. e., the cause of tubal pregnancy. 



The specimens are in most cases accompanied by data bearing upon 

 the cause of tubal pregnancy, and a review of these data shows quite 

 definitely that this condition is associated with inflammatory changes 

 which must have preceded the lodgment of the o\aim in the uterine tube. 

 Under normal conditions the tube is lined with a layer of ciliated 

 epithelium, which constantly works in the direction of the uterus and 

 therefore creates in the tube a stream of fluid from the ovaries to the 

 uterus. The fertihzed ovum is caught up by this stream, and if the 

 conditions are normal is carried into the uterus. Any change which 

 delays the ovum in its progress will favor tubal pregnancy. It is well 

 known that abnormal diverticula or duplicate tubes may be the cause 

 of tubal pregnancy. Numerous isolated cases have been described in 

 which a bhnd tube or large diverticulum contained the implanted ovum. 

 In rare instances, after an operation on one of the tubes, an ovum is 

 subsequently found in its bUnd inner end, whereas the corpus luteum 

 is seen in the ovary on the opposite side, showing that the ovum crossed 



