l6 QUATERCENTENARY STUDIES IN PATHOLOGY 



that it shows secondary stalked structures attached to the deformed 

 palate of the parasite. The question arises as to whether these are to be 

 reckoned a secondary epignathus. 



Representatives of all three embryonic germ layers are present, as is 

 shown in the following table of structures identified : — 



Ectodermal. Mesodermal. Endodermal. 



Skin. Connective tissue. Intestine. 



Hairs. Fat. Thyroid gland. 



Sebaceous glands. Cartilage. Liver cells. 



Sweat glands. Bone. 



Embryonic nervous tissue. Smooth muscle. 



Retinal pigment cells. Blood vessels. 

 Teeth. 

 Salivary gland. 



II.— ON THE STRUCTURE AND RELATIONS OF THE 



EPIGNATHI. 



According to Ahlfeld (i), Hoffman, in 1688, was the first to describe 

 a foetus with a tumour hanging from its mouth. To this condition 

 Geoffroy Saint-Hilaire (^3) gave the name " epignathus," defining it 

 as a faulty developed second head which is attached to the palate of the 

 principal head. 



Ahlfeld (2) says, that, by " epignathus," one understands an acardiacus 

 amorphus which stands in connection with the mouth cavity, mostly with 

 the hard palate of its twin brother. According to his view, all swellings 

 from the mouth of the foetus are derived from a second foetus, even 

 although there are no evident foetal parts. 



More recently, Windle (^^j gives the following definition. " An 

 epignathus, then, is a congenital tumour, teratoid in its nature, or 

 possessing recognisable parts of a foetus, which is attached within 

 the cavity of the mouth or upper part of the pharynx." As he points out, 

 the definition must include all forms, from the simple hairy polypus of the 

 pharynx to the tumour with fully developed portions of a foetus. 



Wittenberg (^7) gives a somewhat wider meaning to " epignathus," and 

 employs it for all teratomata, for which we have to accept, that the first 



(190) 



