Dip Ne IVAN E. WALLIN 
LITERATURE CITED 
ALTMANN, R. 1890 Die Elementarorganismen und ihre Beziehungen zu den 
Zellen. Leipzig. 
Brenpa, C. 1898 Ueber die Spermatogenese der Vertebraten und héheren Inver- 
tebraten. 2. Die Histogenese der Spermien. Verh. d. physiol. Ges. 
Brnsuey, R. R. 1911 Studies on the pancreas of the guinea-pig. Am. Jour. 
Anat., vol. 12. 
Cowpry, E. V. 1914 The vital staining of mitochondria with janus green and 
diethylsafranin in human blood cells. Intern. Monatschrift f. Anat. 
u. Phys., Bd. 31. 
1918 The mitochondrial constituents of protoplasm. Carnegie Inst. 
Publications, Contrib. to Embryology, vol. 8, no. 25. 
Cownpry, N. H. 1917 A comparison of mitochondria in plant and animal cells. 
Biol. Bull., vol. 33. 
FLEMMING, W. 1882 Zellsubstanz, Kern und Zellteilung. Leipzig. 
Loéwscuin, A. M. 1913 Myelinformen und Chondriosomen. Ber. d. deutsch. 
bot. Ges., Bd. 31. 
PLATE 
EXPLANATION OF FIGURES 
All the figures, with the exception of figure 7, were made with the aid of the 
camera lucida. They were all drawn to the same scale. The lenses used were: 
2-mm aproch. oil-immer. obj., comp. ocular no. 8. 
1 Bacillus subtilis from an old culture one hour after the application of Janus 
green. 
2 Bacillus subtilis, a) 5} hours after application of janus green; b) 20 hours 
after application of janus green. 
3 Bacillus subtilis from a 48-hour culture 24 hours after application of janus 
green. 
4 Bacillus megatherium from an old culture 5} hours after application of 
janus green. ‘ 
5 Bacillus megatherium from a 20-hour culture 15 minutes after application 
of janus green. 
6 Bacillus megatherium from an old culture } hour after application of janus 
green. 
7 Free-hand drawing of bacillus megatherium after action of 1 per cent acetic 
acid for a period of six hours. 
8 Bacillus coli 15 minutes after application of Janus green. 
9 Bacillus coli (same specimen as in fig. 8) 5} hours after application of janus 
green. 
