366 B. F. KINGSBURY 



rence of collections of leucocytes in degenerating organs, for example, 

 in the pronephros of lower vertebrates, the gills of anura, thymus, 

 processus vermiformis; also such a possibility may not be at once re- 

 jected in the case of the tonsils (residuum of a visceral cleft) and the so- 

 called trachomal glands (degeneration, of the nictitating membrane?). 

 Certain of the groups of leucocytes found in the mucous membranes 

 are in direct relation to the degeneration of glands (p. 547). 



In most places in the above quotation lymphocyte might be 

 substituted for leuocyte for greater precision. As is of course 

 well known, Stohr ('06) subsequently altered his interpretation 

 of the thymus, coming to regard the ''small round cells" as of 

 epithelial origin and a cell type sui generis, not to be confounded 

 with small lymphocytes. The recent work has not, however, 

 confirmed his second interpretation but rather the former one; 

 with some difference of opinion, however, as to the local or gen- 

 eral (blood) origin or source of the invading cells. The compari- 

 son to which Stohr here refers — that of the thymus and tonsillar 

 structures (whether palatine, lingual, pharyngeal, esophageal, 

 coecal, conjunctival, or elsewhere occurring), as well as the com- 

 parable collections of lymphatic tissue in mucous membranes 

 such as Peyer's patches, solitary nodules, etc. is involved in the 

 interpretation of the thymus insisted on in this paper, and is an 

 important one. Inasmuch as the discussion would require going 

 into the matter in greater detail than is desirable here, and as it 

 is the purpose of the writer to supplement later the prehminary 

 brief paper already published by him (Kingsbury '12), he will 

 only add that, as in the case of the thymus, so in tonsillar struc- 

 tures, the primary local or general origin of the 'lymphocytes' 

 requires further consideration, as well as the relation they 

 bear to regressive epithelial structures (glands). In this con- 

 nection I quote the comment of Stohr in a footnote to the same 

 article quoted from above, apropos the invasion and infiltration 

 of epithelia so characteristic of tonsils, that: 



In the case of the thymus the immigration has the purpose of remov- 

 ing the organ that is of no further use. The leucocytes wander into 

 the epithelium of the tonsils; this is not, however, removed since the 

 crypts of the tonsil are hollow so that the leucocytes so commissioned 

 with its removal suddenly come out on a free surface and reach the 

 mouth cavity without having fulfilled their duty. 



