A NOTE ON THE SPERMATOGENESIS OF TENEBRIO 



MOLITOR. 



RUTH J. STOCKING. 



This study was suggested to me by Dr. Nettie M. Stevens, to 

 whom I am deeply indebted for direction and help during the 

 earlier part of the work, carried on while fellow in biology at 

 Bryn Mawr College in 1912. 1 



The form studied is the common meal-worm, Tenebrio molitor. 

 The worms were kept in the laboratory in a glass jar, and the 

 testes dissected out as needed in the progress of the work. Five 

 methods of fixation were used: Flemming's strong solution, 

 Hermann's platino-acetic-osmic preparation, Gilson's mercuro- 

 nitrate, and Bouin's fluid. After Flemming or Hermann fixation 

 the testes were stained with iron-hsematoxylin, and with safranin 

 followed by gentian-violet or lichtgriin; after Bouin, with iron- 

 hsematoxylin and with thionin ; after mercuro-nitrate, with Auer- 

 bach's fuchsin-green, with thionin, and with iron-hsematoxylin. 



The safranin and lichtgriin staining after either Flemming or 

 Hermann fixation gave the most satisfactory results. By this 

 method the structures of the nucleus were more clearly differ- 

 entiated than by any of the other staining methods. The iron- 

 hsematoxylin and the thionin after any of the fixing agents were 

 next in favor, but they were both useless for some of the most 

 important stages, as they stained linin and chromatin alike. 

 Two of the iron-hsematoxylin slides, however, were destained 

 sufficiently to give a faint differentiation in that respect. Auer- 

 bach's stain was a complete failure with my material; and al- 

 though Miss Stevens and I both tried the Benda method re- 

 peatedly, in no instance did we obtain a typical stain. In two 

 slides of Miss Stevens's the differentiation of the mitochondria 



1 Owing to Miss Stevens's sudden illness and death the work has had to be 

 completed without her supervision. It is only through the great kindness of 

 Dr. T. H. Morgan and Dr. E. B. Wilson, of Columbia University, that I have been 

 enabled to prepare it for publication. My many thanks are due them both for 

 their help and direction. 



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