THE HEMOLYMPH NODES OF THE SHEEP 
Studies on Hemolymph Nodes, I 
CONTENTS. 
Distribution, occurrence and appearance. 
Lymphatic and vascular relations. 
The microscopic structure. 
The cellular content. 
The question of mixed nodes. 
The genesis of intermediate forms. 
Classification. 
Functions. 
References. 
INTRODUCTION 
Although a number of species were investigated, this paper has pur- 
posely been limited to the sheep (Ovis aries), in order that a more com- 
prehensive review of large numbers of hemolymph nodes could first be 
made. For even a slight familiarity with the subject makes it evident 
that it is not only necessary to examine many nodes in the different 
regions of the same animal, but also to examine large numbers in different 
animals, and perhaps of animals of varying ages as well. Moreover, a very 
comprehensive comparative study, although probably indispensable for 
the elucidation of some of the intricate problems of structure, function 
and development, usually introduces many additional and related prob- 
lems which tend to obscure the issue regarding a single species. By 
first subjecting one species to a thorough examination the problem can 
also be better defined, many conflicting statements can be ignored, and 
much confusion avoided. It also seemed probable that an initial and 
careful comprehensive examination of one species would make it possible 
to decide with some degree of certainty whether, as recently and so often 
before reiterated, these organs in a given species are true hemolymph 
nodes or not, and whether a transformation of hemolypmh nodes into 
hemal or lymphatic nodes takes place. To this, and to some other ques- 
