Br. 
Since the adult toads examined were all of them but recently 
transformed (1—4 months after metamorphosis), it cannot be stated 
from the examination so far conducted whether or not the tonsil 
later in the growth of the individual undergoes a regression or not. 
Indeed, in the individual specimens of Salamandra atra examined, 
there was no way of determining the age aside from size, so that the 
“life history’ of these structures remains unknown. It is possible 
that they may have a growth period followed by regression leading 
perhaps to a more or less complete disappearance, — as do the ton- 
sils and thymus of higher forms. Since the sublingual tonsils in the 
largest specimen of Salamandra atra (86 mm) were represented on 
one side only and that by but asmall body, suggested that this might 
be true and that the conditions that induced their development gra- 
dually passed away. 
General. 
The application of the name ‘Tonsil’ to these structures in amphibia 
calls for brief comment. As originally applied (Tonsilla, Amygdalum) 
the name was descriptive of form and form relations. With the work of 
KÖLLIKER (1853) particularly, came the recognition of their lymphatic 
tissue character and the essential agreement with the lingual tonsils 
(Balgdrüsen), pharyngeal tonsil, and lymphatic glands or nodes in 
general. As a natural result of this recognition the tonsils have been 
thought of as simply superficially located lymphatic nodes (glands).*) 
They are, however, more than this. The work since KöLuıker’s 
writings has emphasized as their peculiar characteristic a relation to 
epithelium or epithelial structures, so that on this basis a tonsil might 
be defined as a center (or centers) of cell (lymphocyte) proliferation 
beneath epithelium and intimately related to it. This criterion of a 
tonsil would call for the inclusion of all centers of lymphocyte formation 
related to epithelium wherever occurring and whatever the character 
or origin of the epithelium. One is justified in speaking of a coecal 
tonsil in some forms as has been done. Indeed, a review of what has 
1) Compare Sasın, 1911 in Kriger-Mart; Handbuch d. Entw.-Gesch. d. Men- 
schen, Vol. I], p. 716, “Im Verdauungskanal gibt es gewisse besondere Lymph- 
drüsen, nämlich die Tonsillen, die solitären Follikel und die PEyEr’schen 
Plaques, die sich im Kapillarbett dicht unter dem Epithel entwickeln. Über 
die Entwicklung dieser Lymphdrüsen herrscht ziemliche Verwirrung. Zu 
dieser Verwirrung trug die Annahme bei, daß die vom Epithel stammende 
Thymus lymphoiden Charakter habe.” 
