ANATOMY AND HISTOLOGY OF THE TESTIS 



427 



Chromidial Substance. While no respresentative of the chromidial 

 substance has been discovered in the interstitial cells of the human testicle, 

 isolated basophilic granules do occur in small numbers and have been 

 mentioned by many authors. Their significance is obscure. 



Crystalloid Inclusions. A great variety of crystalloids are to be 

 found in the interstitial cells of different animals. Perhaps the most 

 notable are the crystalloids of Reinke in man. Duesberg has described 

 more numerous and finer crystals than those of Eeinke in the opossum, 



Fig. 3. Interstitial cells of testis of opossum showing (a) secretion within the 

 cells, (b) in the intercellular spaces and (c) in the capillaries, after Duesberg. 



which remind one of those found by Bensley in the thyroid of the same 

 animal. 



Specific Secretory Substances. Many claim to have been able to 

 detect secretion within the cells and in the neighboring blood vessels and 

 lymphatics. It will be sufficient to mention that Mulon regards the diffuse 

 material with intense staining reactions, above mentioned, as lipoidal in 

 nature and the precursor of a true secretion. In this connection the 

 striking physiological effects of the injection of lipoid extracts of the 

 testicle (Iscovesco) are interesting and suggestive. Whether or not the 

 mitochondria take any part in the formation of this hypothetical lipoid 

 secretion remains to be seen. 



Very recently Duesburg has discovered in fixed and stained prepara- 

 tions of the opossum testicle a material with quite definite staining reaq- 



