200 STUDIES ON PATHOLOGIC OVA. 



It seems to me that the studies based upon our collection, as well as recent 

 investigations in experimental embryology, set at rest for all time the question 

 of the causation of monsters. It has been my aim to demonstrate that the em- 

 bryos found in pathological human ova and those obtained experimentally in 

 animals are not merely Analogous or similar, but identical. A double-monster fish 

 or a cyclopean fish is identical with the same condition in human beings. Monsters 

 are produced by external influences acting upon the ovum; as, for instance, varnish- 

 ing the shell of a hen's egg or changing its temperature, traumatic and mechanical 

 agencies, magnetic and electrical influences, as well as alteration of the character 

 of the surrounding gases, or the injection of poisons into the white of an egg. In 

 aquatic animals monsters may be produced by similar methods. Whether in the 

 end all malformations are brought about by some simple mechanism, such, for 

 instance, as alteration in the amount of oxygen or some other gas, remains to be 

 demonstrated. The specimens under consideration show such marked primary 

 changes in the villi of the chorion and in the surrounding decidua that the con- 

 ditions in the human may be considered equivalent or practically identical with 

 those created artificially in the production of abnormal development in animals. 



It would be quite simple to conclude that the poisons produced by an inflamed 

 uterus should be viewed as the sole cause, but when it is recalled that pathological 

 ova occur far more commonly in tubal than in uterine pregnancy, such a theory 

 becomes untenable. Moreover, monsters are frequently observed in swine and 

 other animals without any indication of an inflammatory environment. For this 

 reason I have sought the primary factor in a condition buried in the non-committal 

 term, faulty implantation. It would seem to be apparent that lesions occurring in 

 the chorion as the result of faulty implantation can and must be reflected in the 

 embryo. For example, before circulation has developed in a human embryo, 

 pabulum passes from the chorion to the embryo directly through the exoccelom, 

 and probably on this account we always encounter, as a first indication of patho- 

 logical development, a change in the magma. In older specimens, before any other 

 changes are noticeable in the ovum, the magma becomes markedly increased and 

 a variety of changes are found between the villi. I shall not dwell further upon 

 magma, as I have already dealt with the subject in detail (Mall, 1916). 



It is perfectly clear that, in general, monsters are not due to germinal or 

 hereditary causes, but are produced from normal embryos by influences which are 

 to be sought in their environment. Consequently, if these influences are carried 

 to the embryo by means of fluids which reach it either before or after the circulation 

 has become established, it would not be very far amiss to attribute these condi- 

 tions to alterations in the nutrition of the embryo. Probably it would be more 

 nearly correct to state that change in environment has affected the metabolism 

 of the egg. Kellicott (1916), who has discussed this question, seems to be dis- 

 inclined to accept such an explanation, but I do not see that he has added materially 

 to it by substituting the word disorganization for nutrition, as one might as easily 

 say that the altered nutrition causes the disorganization. 



