4 
HEMOLYMPH NODES OF THE SHEEP 
tions, an unusually large collection of material and a series of observa- 
tions of some magnitude seem to justify a definite, even if not a final or 
necessarily a conclusive answer. 
Although there are many considerations which would seem to 
suggest that the term hemolymph is a misnomer when applied to 
these nodes, this designation, which was suggested by Russel and 
first used by Robertson [24], is retained throughout a part of this 
article in order not to introduce a discussion of terms at the very 
beginning. It is necessary to state, however, that the terms periph- 
eral and central sinuses have been rejected altogether, because no one 
has shown that they are comparable to the corresponding structures of 
lymph nodes. The only true sinuses of hemolymph nodes are the radicles 
of the venous system ; the venous lacunae of Weidenreich ; which struc- 
turally are tremendously dilated capillaries, and which form an integral 
part of the vascular system of the hemolymph node. The so-called per- 
ipheral and central sinuses of the hemolymph nodes can much more 
properly be designated as subcapsular or marginal and central — in the 
sense of internal only — blood spaces or areas, than as sinuses, since they 
are neither in direct communication with either the lymphatic or vas- 
cular circulations, as a rule. 
The sheep was also chosen as the first subject of experiment and 
inquiry, because almost all investigators of hemolymph nodes had studied 
them in this animal to a greater or less extent; because the nodes are 
much more numerous than in any of the other domestic animals 
studied; and since a convenient, inexpensive, and also an abundant 
supply of material was afforded by the abattoirs, where an unlimited 
number of embryos and foetuses of all ages could easily be obtained. In 
addition, however, the carcasses of several dozen new-born lambs, two 
lambs of about five weeks old, and two young sheep six to eight months 
old, received special scrutiny. Besides, several thousand carcasses were 
examined and many thousands inspected in the abattoirs in various parts 
of the country. This varied material naturally afforded an excellent 
opportunity for observations regarding the relation of sex, age, breed, 
pregnancy, states of health and nutrition, castration, locality, seasonal 
changes, and hygienic conditions in general, to the occurrence, size, num- 
ber and position of these "enigmatical structures." Living sheep could 
also be subjected to close scrutiny, the carcasses inspected later, and a 
thorough examination made of the viscera, with a view to detecting any 
possible compensatory relationship between hemolymph nodes and other 
organs, in varying conditions of nutrition and of health. 
