210 



»of occlusiou of the groove go baud in baud with tbe further 

 »development of tbe vascular arrangements in tbe proliferating 

 nlecidual region. It was noticed tbat at tbe coinruencernent tbe 

 » blastocyst reposes at tbe bottom of a groove, which in the 

 »figures just referred to is still seen to be in free communication 

 »with the uterus lumen. Tbis communication is soon interrupted 

 »by tbe combined action of two processes, viz. (a) the soldering 

 *together of the two opposite walls of the depression ; (b) tbe 

 » formation of a blood clot, insignificant in the beginning, but 

 »gradually becoming more massive, wbich is sweated out into 

 »tbe uterus lumen, in consequence of a peculiar haemorrbagic 

 »oedema. Tbis oedema is most distinctly noticed in tbe earliest 

 » stages along the lips of the groove (cf. fig. 2 and 37). In this 

 »region the proliferating bloodvessels very soon become conspicuous 

 »as spacious lumina, that carry a strong flow of blood towards 

 »these lips. The latter, wben the uterus is cut open in the fresh 

 >animal, are, indeed, easily recognised by tbeir deep red, congested 

 > aspect. Tbe process of formation of tbe bloodclot is not wholly 

 »limited to the lips, but it also takes place lower down, along 

 »the sides of tbe narrow groove. In sections bloodextravasates 

 »can often be noticed as passing between tbe epithelium cells, 

 »sometimes heaving these out of their place (PI. XX, fig. 37). 

 »In further stages this bloodclot is seen to contain numerous 

 »remnants of cells that have tbus become detacbed and enclosed 

 » during its formation (fig. 39). After a short time the sides of 

 >the groove approach each other, more especially in tbe vicinity 

 >of the lips, the clot in consequence assuming a more conic shape 

 »in transverse section, with tbe broad end turned downwards, in 

 »the direction of the blastocyst (fig. 3, 7 and 39). Definite fusion 

 »of the two opposite lips of tbe groove is at least reached, the 

 superficial tissue becomes at the same time more congested with 

 »blood than ever, and remnants of the primary bloodclot being 

 » distinctly traceable, both between the fused lips of the groove 

 »and the blastocyst and outside of the former, i. e. in the uterus 

 » lumen. Furthermore there is an accumulation of maternal blood 



