( 813 ) 



The epithelial defect of tlie placental spot is covered by epithelimn 

 advancing fi-oui the edges by a similar process as has become knoAvn 

 of late years for a nnmber of other mammals. Since a spot without 

 epithelium is found in several stages, it must l)e assumed that the 

 covering of the gap does not take place so rajiidly as e.g. in many 

 Rodents. 



Characteristic for the connective tissue is the great abundance of 

 liquid in it; after parturition it appears to be of a loose irregular 

 texture and contains a considerable number of large blood- and 

 especially lymph-vessels, the former especially in the placental spot, the 

 latter spread o\er tiic- ^\•hole mucous membrane. In this connective 

 tissue during the first period following parturition only small and 

 irregularly shaped glands are found, with a low epithelium. These 

 glands occupy little place in the pretty thick mucous membrane. 



In the completely retrograde uterus I find a mucous-connective 

 tissue which is not particularly strong and is rich in cells; in this 

 long glands reach in a very graceful and regular arrangement from 

 the inside of the uterus lo the musculature, while larger blood- and 

 lymi>h-vessels are lacking in it. (see fig. J in Hubrecht's Studies in 

 Manniialian Embryology. Quart, journ. of micr. sc. \'ol. XXX. new 

 ser.). A comparison of these two stages, representing the beginning 

 and the end of the involution, shows the direction of the involution. 

 It consists, not to speak of the just mentioned minor changes in the 

 epithelium, in the connective tissue becoming more compact, the 

 total calibre becoming considerably less, and in a re-arrangement of 

 the glandular apparatus which is probably accompanied by a new- 

 formation, but certainly with a re-arrangement and considerable 

 lengthening of the single glandular tubes. 



In the connective tissue it is not so much the single cells wdiich 

 change (as is e.g. conspicuously the case with the female dog post 

 partum) as there is a clear indication that intercellular substances 

 diminish, which finally leads to a consolidation of the whole tissue. 



At the same time the swollen lympli-\essels become smaller and 

 narrower as well as (he stumps of the torn blood-vessels in the 

 placental spot, the tronibi of which organise themselves. The retro- 

 gression at the placental spot takes place distinctly more slowly 

 than in the remaining mucous membrane so that the placental spot 

 is still recognised as something particular when the gap in the 

 epithelium has become completely covered. 



The return of the glands to their regular form takes still more 

 time than that of the connective tissue, perhaps its last phase only 

 sets in with a new rut. 



57 

 Proceedings Royal Acad. Amsterdam. Vol. VIII. 



