376 MONTGOMERY. [Vol. XV. 



dicken Ring oder ein dickwandiges hohles Ktigelchen darzu- 

 stellen scheint "; while in other cases it may be a simple spot, 

 or may be wholly absent. " Aus meinen Beobachtungen an 

 alien Pflanzen, die eine vollstandige Verfolgung des ganzen 

 Bildungsprocesses erlaubten, geht hervor, dass dieser kleine 

 Korper selbst fruher sich bildet, als der Cytoblast [Nucleus]." 



Macfarlane ('81) examined various plant cells, in all of which 

 he found one or several bodies (" nucleolo-nuclei ") within the 

 nucleolus. The nucleolus of Spirogyra has a distinct membrane, 

 which disappears at the period of the nucleolar division ; the 

 karyokinesis results in the formation of a "nuclear barrel," at 

 each end of which is a mass of nucleoplasm, these two masses 

 being connected by fibers with the nucleolus which lies between 

 them. The nucleolus then divides, preceded by a division of 

 the nucleolo-nucleus, so that each daughter-nucleolus receives 

 a daughter nucleolo-nucleus, and the daughter-nucleoli then 

 wander apart to the nearest masses of nucleoplasm, " as they 

 retreat from each other they drive the polar masses before them, 

 thereby elongating the nuclear barrel. . . . The nucleoli at 

 length advance to the polar masses and bury themselves in 

 the nucleoplasm of these." From these and numerous other 

 observations, Macfarlane concludes : "that the nucleolus, or 

 more probably the nucleolo-nucleus, is the center of germinal 

 activity, and that as we pass outwards to the periphery of the 

 cell, this reproductive activity becomes less and less. In no 

 other way, to my mind, can the number of nucleoli and nucleolo- 

 nuclei at different ages in the cells of any plant be explained." 



Strasburger ('82a) gives reviews of previous observations on 

 the chemical constituency of nucleoli. 



Strasburger ('82b) studied nuclear division in various plant 

 cells (Fritillaria, Lilium, Hemerocallis, Tradescantia, Galantlius, 

 Dicotyledons). " Pollenmutterzelle " of Fritillaria : between 

 the nucleus and its membrane collects a homogeneous, refrac- 

 tive, lens-shaped mass of substance; " sie geht nicht unmittelbar 

 aus den Kernkorperchen hervor, die ja schon auf vorausgehenden 

 Stadien verschwunden waren, vielmehr reprasentirt sie, allem 

 Anschein nach, ein Secret"; this body he terms " Secretkor- 

 perchen." At first it stains deeply with methylen green ; but 



