296 STUDIES ON PATHOLOGIC OVA. 



forms likewise have been described as normal, and macerated normal specimens 

 also as pathologic, although no one would, I presume, defend the opinion that a 

 dead conceptus may become pathologic. 



Although His emphasized that the softness of aborted forms easily results in 

 unusual folds and flexures, he, it seems, greatly reinforced, even if he did not intro- 

 duce, the idea that embryos that are abnormal in form are pathologic. He 

 apparently came to this conclusion because he did not believe that post-mortem 

 changes could be responsible for modifications in form present in the specimens 

 which came to his attention. Giacomini (1888) also believed that many of the 

 deformities so common in embryos of the first months are due purely to regression 

 after death, but added that he did not care to stress the idea that post-mortem 

 changes can account for many of the deformities seen. Later Giacomini evidently 

 became skeptical, however, and decided that it remained to be determined whether 

 the changes in the embryo are primary or secondary. Furthermore, in 1894, he 

 declared that one never meets with changes in abortive forms which one can 

 attribute solely to softening, and concluded that embryos that die soften and dis- 

 integrate quickly, only those which merely are inhibited in growth being preserved 

 for months. Waldstein (1913) also stated that von Winckel spoke of a slowing of 

 development before death of the embryo occurred. While it is conceivable, and 

 even probable, that inhibition in growth may occur, experiments now under way 

 show that dead mammalian fetuses nevertheless may be preserved in sterile nutrient 

 and non-nutrient solutions at body temperature for extended periods of time for 

 months without indication of growth and with very little change in external form. 



Although one must frankly recognize that it is extremely difficult to simulate 

 intrauterine conditions closely, these experiments nevertheless very seriously 

 question the conclusion of Giacomini. His (1891) also emphasized that dead 

 embryos may be preserved in utero for months, and there is abundant evidence in 

 the Carnegie Collection corroborating this conclusion. But it is conceivable that 

 slight modifications in body-form might arise from gradual inhibition in growth, 

 as well as from post-mortem changes of secondary origin. Panum (1860), in dis- 

 cussing what he termed monstruositates Males amorphoides occurring among chicks, 

 also expressed the opinion that the changes in embryonic form noticed by him arose 

 during life. He claimed that these changes could not have resulted from macera- 

 tion, because adhesions of the membranes were present, because the specimens 

 showed a total divergence from the normal form, and also because of the differences 

 in size and consistency found to exist among them. Panum was led to the conclu- 

 sion that all the deformities noticed by him in chicks were the result of the condi- 

 tions under which development occurred and through the absence of evidence 

 supporting the opinion of Bischoff that the cause of monsters was germinal. But 

 Panum nevertheless believed that gases formed from putrefaction might com- 

 press the embryo and produce a fetus papyraceous. 



When considering these greatly modified or even bizarre forms of human 

 embryos, one also is reminded of the fact that Panum believed that monstrous 

 chicks resulted directly from a lowering of the temperature during incubation. 



