66 The Normal Histology of the Human Hemolymph Glands 



normal animals. As a result of this study the following conclusions 

 regarding the normal histology of the human hemolymph glands have 

 been reached. 



Technique. — The thymus, anterior mediastinal and renal regions are 

 examined in the usual order of the autopsy; the prevertebral tissues at 

 the close of the autopsy. The neck-organs, thoracic and abdominal 

 vessels, root of the mesentery, and other structures attached are strip- 

 ped from the spinal column from above downwards and removed from 

 the body for minute examination. When there is much prevertebral 

 fat present or when the tissues are very opaque the search for hemo- 

 lymph glands may be made much more successful by first fixing the 

 tissues in mass in 4 per cent formalin. The color of the blood-sinuses 

 is in this way brought out much more sharply, and the glands may be 

 recognized when the search in the fresh tissue would have been nega- 

 tive. When it is desired to study the exact position and relations of 

 these glands the prevertebral tissues should be dissected in place and 

 not stripped from the spine. Since the sinuses of the human hemo- 

 lymph glands partly collapse after death the recognition by color alone 

 is not easy and at times impossible. It therefore becomes necessary to 

 remove all glands found in a region for microscopical diagnosis and 

 in many cases it is only in this way that the character of a gland can 

 be definitely determined. In the search for these glands in the human 

 body their proximity to large vessels should be borne in mind; they 

 occur very frequently in the connective tissue between artery and vein. 



OccuREENCE. — Taking the presence of a sinus containing blood in 

 place of lymph as the essential feature of a hemolymph gland, such 

 glands are found constantly present in the human body. They are 

 apparently more numerous, at least are more easily recognized, in early 

 adult and middle life than in infancy or old age. In new-born children 

 they are discovered with difficulty, and usually can be found only after 

 microscopical examination. In late life they become atrophic, the 

 blood-sinuses being obliterated for the greater part by connective-tis- 

 sue increase. No difference in their occurrence has been observed in 

 the sexes. With the individual they apparently differ very much as re- 

 gards their location, number and size, seldom being found under ex- 

 actly similar conditions; but owing to the difficulty of recognizing them 

 with the naked eye it is probable that these variations may be only 

 apparent, resulting from imperfect technique. 



They are found in greatest numbers in the prevertebral retroperi- 

 toneal and cervical regions, in the neighborhood of the adrenal and 

 renal vessels, along the brim of the pelvis, in the root of the mesen- 



