INTERSTITIAL CELLS OF THE CHICKEN TESTIS. 



149 



just-hatched chicks, and there are here also no cells differentiated 

 from the connective tissue fibers. In the adult there are more 

 elongated nuclei and fewer round ones. In the testis, where the 

 tubules are large, and crowded close together, so that there is 

 not much interstitial tissue between them, the nuclei are mostly 

 elliptical, with some round ones in the triangle (Fig. 6). Where 

 the tubules are small and far apart, leaving much interstitial 

 tissue there are more round nuclei, and they lie not only in the 



FIG. 6. Same as Fig. 5, but from cf 2323, showing few nuclei and few fat 

 globules. B = blood vessel. X 1,000. 



triangles (Fig. 5). In counting the nuclei as mentioned above, 

 I differentiated between long and round ones. Table I. shows 

 the mean number of each kind, and Table II. gives the percentage 

 of each shape to the total number of nuclei. In cfs 666 and 

 1271, with the small tubules, 48 per cent, and 44 per cent, nuclei 

 are long, but in cTs 147 and 2323 where the tubules are large, 

 66 per cent, and 64 per cent, are long. This relation must mean 

 a difference in mechanical conditions of pressure. 



If the difference in the cells of the interstitial spaces is in the 

 shape of the nuclei, and the shape of the nuclei is merely due to 

 mechanical causes, can we call any of these cells interstitial cells 

 with the accepted meaning of the word? We could form a 

 complete series of nuclei ranging gradually from the typical 

 elliptical connective tissue nuclei to the round undifferentiated 



