474 IVAN E. WALLIN 



chondria. The author beUeves that his results on the root-nodule 

 bacteria were due to this technique. For illustrations of the 

 three forms of Bacillus radicicola, the reader is referred to an 

 article by the author (Wallin, 1922b). 



Murray (1919) has recently recommended the use of mito- 

 chondrial technique in certain cases where the Gram stain, for 

 example, does not give differential results. 



The author also wishes to call attention to the action of janus 

 green when applied to bacteria. All bacteria, apparently, are not 

 stained by janus green, but certain strains are and, apparently, 

 only under certain conditions. This is a vital stain and it is 

 possible that it may be found useful in the study of certain 

 bacteria. The reader is referred to Cowdry (1918) for directions 

 and information regarding the proper brand of janus green. 



REFERENCES 



Benslet, R. R. 1911 Studies on the pancreas of the guinea-pig. Amer. Jour. 

 of Anat., 12. 



Bewley, W. F., and Hutchinson, H. B. 1920 On the changes through which 

 the nodule organism (Ps. radicicola) passes under cultural conditions. 

 Jour. Agr. Sci., 10, 2:144-162. 



Cowdry, E. V. 1918 The mitochondrial constituents of protoplasm. Carnegie 

 Inst. Pub., Contib. to Embry. 8 , 25. 



LoHNis, F. 1921 Studies upon the life cycles of the bacteria. Pt. 1. Memoirs 

 Natn. Acad. Sci., XVI :2nd mem. Wash. 



LoHNis, F. AND Smith, N. R. 1916 Life cycles of the bacteria (Preliminary 

 communication). Jour. Agr. Research, 6, 18. 



Murray, J. A. 1919 Sixth Scientific Report of the Imperial Cancer Research 

 Fund, p. 77. 



Wallin, Ivan E. 1922a On the nature of mitochondria. I. Observations on 

 mitochondrial staining methods applied to bacteria. II. Reactions 

 of bacteria to chemical treatment. Amer. Jour. Anat. 30 , 203. 



Wallin, Ivan E. 1922b On the nature of mitochondria. III. The demonstra- 

 tion of mitochondria by bacteriological methods. IV. A comparative 

 study of the morphogenesis of root-nodule bacteria and chloroplasts. 

 Amer. Jour, of Anat. (In press.) 



