RESORPTION OF CONCEPTUSES. 305 



The phenomenon of intrauterine lysis is interesting also from a 

 chemical standpoint. What the antomist would like to know 

 is not merely in what respects the composition of the intra- and 

 peri-amniotic fluids has been changed, but just what the enzymes 

 are that have caused a complete lysis of the embryo ; where these 

 first arise and act; and how and why they become active. These, 

 and many other questions the chemist only can answer. For 

 this answer fresh material is indispensable, but this the neigh- 

 boring practitioners or a closely associated clinic can supply. 

 That the lysis of these early embryos and undoubtedly also of 

 the chorionic vesicles is not due primarily or even very materially 

 to phagocytic activity is very evident even upon cursory examin- 

 ation. In the presence of the intact chorionic and amnionic 

 vesicles in some specimens, such a process is wholly excluded. 

 Besides, one never sees any evidence of phagocytosis of the 

 preserved fetal by the maternal tissue in human conceptuses. 

 Evidences of the contrary process are not wanting. 



That the embryo or fetus usually is the first member of the 

 conceptus to disappear has already been implied by stating that 

 in 32 per cent, of the abortuses grouped as pathological in the 

 Mall Collection, the embryo is missing. Although the absence 

 of the embryo does not necessarily mean, in every case, that it 

 underwent complete autolysis, this no doubt is true in by far the 

 great majority of these cases. The fact that the embryo disap- 

 pears first may be due to a lower resistance on its part than that 

 possessed by either amnion or chorion, or to a preponderance of 

 enzymes within it. Autolysis of the body of the embryo before 

 that of the membranes, also may be due to the fact that the 

 adnexa, especially the chorion, or at least parts of it, often pre- 

 serve vitality long after the death of the embryo because of the 

 direct relation to the uterus. Nevertheless, it often is surprising 

 how long the form of a small retained fetus or even of the amnion 

 apparently has been preserved, although it should be remembered 

 that in some cases the preservation of external form gives little 

 indication of the true state of the constituent tissues. If the 

 advent of proteolytic fat-, and carbohydrate-splitting enzymes 

 in fetal tissues is gradual, the surprisingly long time during which 

 some of the small embryos are preserved may be due in a con- 



