163 



spaces also as raaternal. At the same time he recognised that the 

 cells liniug them agreed in every character with cells of known 

 embryonic origin ; hence the 'piasmode endovasculaire'. 



I regret very much that I should have been compelled to differ 

 so fundamentally from Professor Duval; but 1 hope that I may 

 none the less be permitted to express my sincere admiration for 

 the work of an embryologist who has invariably taken the trouble 

 to examine a complete series of stages before he has allowed 

 himself to make a statement concerning any one of them. 



There is one another point which I must briefly touch upon, 

 concerning, namely, the cells with the brown, iron-containing 

 granules. 



Duval has seen these in the post-partum uterus and says that 

 they arise from masses of blood situated at the points of attach- 

 ment of the p'acental of the last gestation. He does not appear 

 to have identified the brown substance as an iron-compound. 



I cannot quite agree with him when he says that the placental 

 of the next pregnancy are always situated alternately with the 

 masses of brown cells; at any rate I have found a young blasto- 

 cyst fixed in one of these regions. 



The papers of Burckhard (4), Nussbaum (34), and Klebs (24) 

 require very little notice. 



The first-mentioned has only described the early stages of fixa- 

 tion, and has not much to add to DuvaFs account. He disting- 

 uishes two kinds of mitosis in the subepithelial tissue, in the 

 endothelium, namely, and in the 'decidual' cells; and he points 

 out quite correctly that the lumen of the uterus is always ex- 

 centric (nearer the mesometrium) even in the non-pregnant uterus ; 

 and further that at the actual point of attachment of the blasto- 

 cyst the uterine epithelium does not so much degenerate as break. 



I cannot ho wever agree with him when he attributes a 'decidual' 

 origin to the megalokaryocytes, nor when he says that the ori- 

 ginal lumen of the uterus becomes separated by a bridge of 

 'decidual' tissue from the pit in which the embryo is imbedded. 

 His figures 8 and 9 appear to me to be merely oblique sections; 



