152 



ALICE M. BORING. 



If interstitial cells or cells of interstitial connective tissue are 

 secreting the fat found in the testis we certainly would expect to 

 find it abundant in such an "interstitial gland," or if we prefer 

 not to use that term, in so large a mass of interstitial tissue. 

 However, there is not so much fat as in some of the smaller 

 triangles and narrow spaces. This study shows no evidence that 

 the fat in the active testis is formed by the interstitial cells. 



FIG. 9. Part of an " interstitial gland " in G? 666, showing many round nuclei, 

 but comparatively little fat. X 1,000. 



It seems likely that this fat is being brought to the testis by 

 the general metabolic processes possibly in connection with sexual 

 activity, just as fat is deposited in the yolk of eggs in the hen. 

 This would fit in with the former suggestion that possibly the 

 testis in d" 666 is not as far developed as 147 and 2323. The 

 tubules in 666 are smaller and the quantity of fat is greater. 

 It may be in the process of active growth, while 2323 has reached 

 the climax of growth of tubules, and used up most of the fat for 

 this growth. 



SUMMARY. 



In conclusion, then, I find no cells in the interstitial tissue in 

 the young or old chicken testis with the cell bodies differentiated 

 from the connective tissue fibers. No evidence has been found 

 that differences in shape of the nuclei are indicative of functional 

 differences in the various cells of the interstitial tissue. On the 



