ON THE INTERSTITIAL CELLS OF THE TESTICLE 



IN DIDELPHYS. 



J. DUESBERG, 



CARNEGIE INSTITUTION OF WASHINGTON, DEPARTMENT OF EMBRYOLOGY, 



BALTIMORE, MD. 



I completed a short time ago a study of the seminal cells of 

 Didelphys, to appear (1919) in Contributions to Embryology, 

 published by the Carnegie Institution of Washington, in a 

 memorial volume dedicated to the late Professor Franklin P. 

 Mall. While making that investigation I was struck by the 

 large number of interstitial cells present in the testicle of the 

 opossum, and, upon closer observation, by the complexity of 

 their structure. I therefore determined to undertake a study of 

 these cells. 



The material upon which it was based consisted of nine animals. 

 Five were full grown, a sixth exhibited all stages of spermiogenesis 

 except the very last i. e., the formation of the spiral filament at 

 the expense of the chondriosomes and the remaining three were 

 in a much less advanced stage of development. Fragments of 

 the testicle were fixed in the following fluids: Hermann's, Ramon 

 y Cajal's mixture of formalin and uranium nitrate (1912), 

 Bouin's, Flemming's, Altmann's, Meves', Benda's, Regaud's, 

 acetic sublimate and saturated sublimate. Two adult animals 

 were sacrificed in order to study the living cells, and were injected 

 with a solution of janus-green (1-10,000 in 0.85 per cent, salt 

 solution). I am greatly indebted to Professor E. V. Cowdry for 

 his help in carrying out these experiments. 



Of the above mentioned reagents Benda's, Meves', Regaud's 

 and Altmann's fluids were used for the purpose of fixing the 

 chondriosomes. To stain these bodies iron-hematoxylin, Benda's 

 and Altmann's methods, and a combination of acid fuchsin and 

 methylgreen were employed. Ramon y Cajal's mixture of 

 formalin and uranium-nitrate was applied in order to bring into 

 evidence the apparatus of Golgi. The best preparations were 



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