Aldred Scott Warthin 67 



tery but rarely extending far out into it, still more rarely in the 

 omentum and epiploica. In normal individuals they are rarely found 

 in the mediastinal tissues or along the thoracic vertebrae, but in cases 

 of a,nemia in which the hemolymph glands throughout the entire body 

 are enlarged they may be found in large numbers in these regions mak- 

 ing it appear probable that under normal conditions they are of such 

 small size as to escape notice. In the cervical region they are usually 

 found below and behind the lobes of the thyroid in association with 

 the parathyroids. 



Gross Appeaeances. — The human hemolymph glands are not nearly 

 so easily recognized by the naked eye as are those of the steer and sheep, 

 because of the fact that their blood-sinuses are frequently collapsed and 

 partly emptied after death. They usually lie deeply embedded in fat 

 or connective tissue, and as a rule near the wall of some large vessel. 

 As a rule only a few show distended sinuses, these glands are deep-red 

 or bluish in color and may be easily mistalsen for hemorrhages, blood- 

 clots, or deeply-congested lymph glands. The resemblance to spleen- 

 tissue is often very close. In the transition forms which are partly 

 hemolymph glands and partly ordinary lymphatic glands the blood- 

 sinuses appear as red points or streaks. It is often difficult or impos- 

 sible to distinguish these from congested lymph glands. The smallest 

 hemolymph glands may often be found by stretching the tissue against 

 the light, the blood-sinuses then appearing as red points or lines. Fixa- 

 tion of the tissues in formalin is of great advantage as the blood-con- 

 tent of the sinuses of these glands is brought out in sharp contrast to 

 the lighter color of lymphoid tissue. When the blood-sinuses are small 

 or few in number the gland cannot be distinguished on naked-eye in- 

 spection from an ordinary lymph gland. It is, therefore, safest in 

 studying the occurrence of hemolymph glands to remove all apparent 

 glandular structures and examine them microscopically. 



On cross-section the blood-sinuses resemble spleen-pulp and contrast 

 according to their blood-content more or less sharply with the whitish 

 areas of lymphoid tissue. Small round masses of whitish lymphoid 

 tissue often project into the pulp-like peripheral sinus suggesting 

 splenic follicles. Partly collapsed and emptied sinuses appear as points 

 and streaks of red. The presence of a peripheral red streak just be- 

 neath the capsule of the gland with red lines radiating toward the center 

 of the gland is a very important point in the naked-eye diagnosis of 

 these organs. Occasionally the capsular surface of a hemolymph gland 

 is studded with small beaded elevations, giving it a raspberry appear- 



