173 The Development of the Interstitial Cells of Leydig 



quantity of a loose cellular tissue. The constitution of this tissue is 

 shown very well by Mallory's stain. In sections thus stained (Fig. 1) 

 it is seen to be composed of a mixture of cells and fibrils. The cells 

 often have little or no cytoplasm, some appearing to be mere naked 

 nuclei; but others show a collection of cj'toplasm at one pole. The 

 nuclei are spherical or ovoid, except when closely packed together, in 

 which case they incline to the spindle-shape. They contain much 

 nuclear sap in which is a network of chromatin; and usually there is a 



Pig. 1. Pig 22 mm. Shows the structure of the intertubular tissue. Mallory's con- 

 nective-tissue stain. X 800. 



quite distinct nl^cleolus. Mitotic figures are present here and there. 

 The cells or nuclei are imbedded in a network of fibrils which take the 

 aniline-blue of the stain. It seems clear that this tissue is a young 

 connective-tissue syncytium in the sense of Mali/ In all essentials it 

 is quite similar in structure to the deeper layers of the albuginea, with 

 which it is continuous, and to the mesenchyme in general. 



Leydig's cells were first definitely encountered in embryos 24 mm. 

 long. In the sections they appear scattered about in the intertubular 



® On the Development of the Connective Tissues from the Connective-Tissue 

 Syncytium. Amer. Jour. Anat., Bait., 1902, Vol. I, No. 3. 



