290 



Society Proceedings (122). 



as bacteriostatic, since it seems to consist essentially in an in- 

 hibition of growth. It is probable that this parallelism between 

 the bacteriostatic and the bactericidal activity of the dye, so 

 clear cut in the case of gentian violet, does not hold in the case of 

 acid fuchsin and sodium chloride. The evidence thus far gathered 

 would indicate that the mechanism by which growth is inhibited 

 may be entirely different from the mechanism by which organisms 

 are killed. 



128 (1875) 



On the method of macronuclear disintegration during endomixis 

 in Paramecium aurelia. 



By LORANDE LOSS WOODRUFF and HOPE SPENCER. 



\From the Osborn Zoological Laboratory, Yale University, New Haven, 



Conn.] 



In the original studies 1 of the nuclear phenomena involved in 

 endomixis, it was found that macronuclear disintegration, both in 

 Paramecium aurelia and Paramecium caudatum, was effected by 

 the elimination of spherical chromatin-bodies from the macro- 

 nucleus, instead of by the transformation of most of the macro- 

 nucleus into long tangled chromatin-ribbons such as occurs during 

 conjugation in these species. Regarding Paramecium aurelia, 

 it was stated that the "differences between the macronuclear 

 changes during conjugation and during the process (endomixis) 

 are only morphological; on the one hand, the macronucleus forms 

 1 wurstformige Schlingen,' while on the other, the macronucleus 

 eliminates its chromatin by extruding it in the form of spherical 

 bodies." 2 



This contrast proved valid not only in Woodruff's pedigree race 3 

 (I) of Paramecium aurelia in which endomixis was discovered, but 

 also in animals from such diverse sources as Germany and Ohio. 

 Only one cell {Paramecium aurelia, I), 4087th generation, Decem- 



1 L. L. Woodruff and Rhoda Erdmann, Jonrn. Exper. Zoology, 1914, xvii, 425- 

 517. Erdmann and Woodruff , Journ. Exper. Zoology, 1916, xx, 59-97- 



2 Woodruff and Erdmann, loc. cit., pp. 438-39, and 444; Plate 1, Figs. 9 and El; 

 Plate 2, Fig. 14; Plate 3, Fig. 32. 



•Woodruff, Biological Bulletin, 191 7, xxx, 51-56. 



