1906.] PLACENTA IN UNGULATES. 93 



I have found exactly similar bodies in the Pig, although, as I only- 

 obtained these with the after-birth, I cannot say whether they were 

 inside the allantois or on the outside of the chorion. From these 

 I succeeded, by drying, dissolving in chloroform, and crystallizing- 

 out, in obtaining small lanceolate and rhomboidal crystals of 

 bilirubin (text-fig, 33). 



These small bilirubin bodies of the Cow are found principally 

 in the cotyledons. Later on they seem to lose their bile-pigment ; 

 for between the extra-cotyledonary trophoblast and the uterus 

 only bodies of a paler yellow are found. The allantoic bodies are 

 nearly white. 



Text-fi^. 33. 



Rhomboidal and lanceolate crystals of bilirubin obtained from a cliloroform 

 solution of the dried allantoic bodies of tlie Pig. Drawn with Zeiss obj. 2 mm. 

 achr., comp. oc. 6. 



The bilirubin appears to arise by further modification of the 

 yellow-brown pigment of the placenta ; but whether it is formed 

 inside trophoblastic cells from ingested corpuscles and then passed 

 out, or whether it arises extra- cellular ly in the maternal extra- 

 vasations, and if so, whether its formation is due to any dip-estive 

 activity of the trophoblast or not, I am afraid I am unable to 

 say. From the analogy of what occurs in such extravasations 

 as bruises, it would appear that the hsemoglobin derivatives 

 might be formed, not only inside (as is undoubtedly the case), 

 but also outside the cells of the trophoblast ; for the yellow- 

 brown pigment described in the last section certainly occurs, not 

 only in the blood-extravasations in the crypts, but even in the 

 maternal tissues and blood-vessels (Plate III. fig. 4). 



List of Woi^ks referred to in the Text. 



Bernard, C. Legons sur les phenom^nes de la vie. Paris, 1879. 



. " Memoire sur une nouvelle fonction du placenta." Ann. 



Sci. Nat. (4) X. 1858. 



Bonnet, R. " Die Uterinmilch und ihre Bedeutung fiir die 

 Frucht." Festschrift fiir Bischofi". Stuttgart, 1882. 



. " Beitrage zur Embryologie der Wiederkauer gewonnen 



am Schafei." Arch. f. Anat. u. Phys. (Anat.) 1889. 



BuNGE, G. Text-book of Physiological and Pathological Che- 

 mistry. Enghsh translation by L. C. Wooldridge. 

 London, 1890. 



