( 877 ) 



These cells also are gradually dissolved into blood-corpuscles: as 

 the uterus grows and the trophospongia passes through its successive 

 developmental stages, they disappear: the blood-corpuscles which owe 

 their existence to them, fall into the above-mentioned spaces, from 

 whence they are taken up in the further circulation. The intermediate 

 stages that can be observed in this way of blood-formation, are in 

 fact an increase of nuclei by amitosis, as was also described by 

 Pouakoff and later a gradual formation from these nuclear derivates 

 of non-nucleated blood-discs. 



To these two processes of blood-formation in the placenta of 

 Galeopithecus a third must be added in which not the mother is 

 the active agent, as in the two former cases, but the embryonic 

 trophoblast. Of this trophoblast we described above how it forms 

 the bottom of the cavities into which the newly-formed blood-corpus- 

 cles are discharged, and how it coalesces with the maternal trophos- 

 pongia to such an extent that for many cells, which here are closely 

 adjacent, it is impossible to determine whether they take their origin 

 in the mother or in the trophoblast of the germinal vesicle. 



Yet in regard to the wall of the cavities, which separates them 

 from the lumen of the uterus, there can be no doubt that we have 

 here trophoblastic tissue only. About the active proliferation of this 

 trophoblast tissue there is no doubt, no more than about the question 

 whether the numerous parts of this trophoblast that project into the 

 cavities, partake in the haematopoiesis. As soon as these parts are 

 examined with strong powers it is quite evident that here the nuclei 

 of the trophoblast cells undergo similar modifications as were describe» I 

 above and that the final product of these modifications are again red 

 non-nucleated blood-corpuscles which are added to those already present 

 and originating from the mother. Now these corpuscles are, in the 

 same way as I observed ten years ago in Tarsius and Tupaja, 

 set free into ike maternal circulation and carried along la/ it. 



On the theoretical significance of the tact that the germinal vesicle 

 takes an active and important part in increasing the number of 

 units for the transport of oxygen in the maternal blood, I will not 

 expatiate here. 



And for the histological details of the formation of the bloodplates, 

 resp. non-nucleated blood-corpuscles from an originally normal cell- 

 nucleus, I refer to the coloured figures of pi. I and II of Pol.jakoff's 

 paper in the 1901 volume of the Arch. f. Anat. u. Phys. (Anat. 

 Abth.). With his illustrations I can identify everything I have ob- 

 served in Galeopithecus. While in a very few cases there seems 

 to be a possibility that the blood-corpuscle owes its existence to a 



