338 ON GROWTH AND OVERGROWTH 



Example : Foetal inclusions. 



(2) Filial Teratomas. — Due to the growth within the tissues 

 of the one individual of the products of a totipotential cell derived 

 from that individual. 



(a) Blastomeric Teratoma, due to the segregation of a (toti- 



potential) blastomere in the early embryonic or 

 " germinal " period (Ballantyne) and subsequent 

 growth. 

 Examples : Three-layered epignathus and congenital sacral 

 teratoma. 



(b) Germ-cell Teratoma, due to independent, aberrant growth 



of a totipotential germ cell at any period after the germ 

 cells, as such, become segregated from the somatic cells 

 of the embryo, and before the nuclear reduction pro- 

 cesses take place which lead to the production of 

 oocytes and spermatozoa. 

 Examples : Ovarian and testicular dermoids . 



II. Terato-blastomas. — The products of growth of a segregated 

 pluripotential cell of the individual. 



Examples : Two-layered and simpler forms of epignathus 

 and " congenital sacral teratoma " ; also " Mischgeschwulste " 

 (embryomas of Wilms) of kidney, parotid, etc. 



III. Blastomas. — The products of growth of a segregated 

 unipotential cell. 



(1) Teratogenous, due to continued aberrant growth of uni- 

 potential cells of one individual (the embryo, or, rarely, of a 

 teratoma) within the tissues of the other (the parent). 



Examples : Placental moles and chorio-epithelioma malignum. 

 Carcinomas, etc., originating in ovarian dermoids. 



(2) Common, derived from unipotential cells of the host. 

 Examples : The ordinary neoplasms formed of one type of 



tissue — fibroma, adenoma, etc., sarcoma, endothelioma, car- 

 cinoma, etc. 



It is these blastomas that can be subdivided according to 

 my previous classification into the lepidic or lining membrane 

 tumours (lepidomas) and the hylic or matricial tumours (hylomas), 

 whether of epiblastic, hypoblastic, or mesoblastic (mesothelial 

 and mesenchymatous) development. 



IV. Blastomatoid Growths. — There is yet a fourth class of new 

 growths so called, not coming into any of the above categories, 



