84 CARNEGIE INSTITUTION OF WASHINGTON. 



the difficulties linked with scarcity of material and that the cyclic histological 

 changes of the human genital tract are very imperfectly known. This labora- 

 tory was fortunate in recently receiving a specimen which appears to me to 

 have a significant bearing upon this general problem and which, in conform- 

 ance with Dr. Corner's investigations, indicates that abnormalities of develop- 

 ment in man are to be frequently attributed to factors influencing the early 

 ovum rather than to the environment at the site of implantation. The 

 specimen consists of a fetus which died at about the twentieth week and, being 

 retained in the uterus, thereafter underwent maceration and alteration in 

 form. The attached placenta showed a correspondingly marked degenera- 

 tion. The whole picture is one commonly met with in abortion material. 

 That the environment was not the cause of defective development in this case 

 is proved by the circumstance that it was a double-ovum pregnancy in which 

 the other ovum went through to term as a normal living baby. The normal 

 and abnormal placentae are directly contiguous and so must be regarded as 

 exposed to essentially the same surface and environment. At their junction 

 there is an abrupt demarcation, on one side of which the villi are in an advanced 

 stage of fibrinoid degeneration, while on the other they are entirely normal. 



Whereas we have seen that ova may result in defective embryos in spite 

 of a normal environment, it is also true that under some circumstances an 

 ovum may develop normally in an abnormal environment, as is shown in 

 ectopic pregnancies. A unique case of this kind was reported by me during 

 the past year, in which a human ovum became implanted and underwent 

 development entirely outside of the abdominal cavity, in the superficial fascia 

 of the abdomen, forming a tumor just under the skin. In spite of this 

 abnormal environment, at the time of its removal the ovum had reached the 

 size of a hen's egg, and both the embryo and chorionic sac were normal. The 

 case was one in which a ventral fixation of the uterus had been performed and, 

 through mistake, the Fallopian tube had been pulled through the rectus 

 abdominis muscle, which presented a pathway by which the ovum reached its 

 unusual implantation site. 



Whether abortions and defective development are due to environment 

 (faulty implantation) or to the composition of the germ-plasm is a matter of 

 great clinical importance, for knowledge on this point must be had before 

 intelligent treatment can be administered. This problem has been studied 

 by Dr. J. L. Huntington, who has reported on 398 cases of pregnancy, of which 

 39 were terminated before the end of the twenty-eighth week. Of these, 27 

 were cases of inevitable abortion, in most of which the lifeless embryo had 

 been retained from three to eight weeks before its expulsion. In these cases 

 it was apparent that germinal defects played a greater role than disease of the 

 genital tract. Dr. Huntington points out the importance of determining 

 the size of the uterus as early in pregnancy as possible, and where there is 

 bleeding without adequate uterine enlargement, to assume the death of the 

 fetus and permit the emptying of the uterus through its own contractions or, 

 if necessary, accomplish it by operative procedure. 



Abnormal Development of the Hindgut. 

 Dr. J. C. Baldwin has studied the morphology of a fetus with entero- 

 urethral fusion in which there was an enormous distention of the bladder. 

 So great was the consequent enlargement of the abdomen that the case was 



