42 Mr Allan E. Graut on the 



StrasV)urger * has coufirmed tlie observations uf Hegel- 

 maier and Johow in all important points. In the vegetative 

 cells of Dicotyledons fragmentation does not appear to be 

 so common as in those of Monocotyledons. He has seen 

 it occurring, however, in very old cells of the pith of 

 Tropoeolum mo.jus and in species of Nicotiana shortly before 

 disintegration of the nucleus. According to Strasburger, 

 the two phenomena of division and fragmentation of the 

 nucleus are not identical. Division of the nucleus takes 

 place in cells with vital activity, and under the influence 

 of the surrounding protoplasm ; fragmentation, on the con- 

 trary, is a process belonging to the nucleus only, which 

 does not begin until the influence upon it of the surrounding 

 protoplasm has cea-sed. The cell may remain for a long 

 time in the multinucleated condition, but in many cases it 

 rapidly leads to disorganisation of the nucleus. 



M. Priilieux f describes the multiplication of the nuclei 

 in the cells of the root of a plant grown in soil the tem- 

 perature of which generally exceeded by about 10° that of 

 the surrounding atmosphere. There were from two to 

 four nuclei in each cell, and they were either isolated or 

 united into a mass, and pressed against one another. They 

 frequently varied in form and size. They multiplied by 

 fragmentation, and often contained a immber of nucleoli of 

 various forms and sizes. The hypertrophied nuclei are 

 vesicular, and the protoplasmic mass dense and finely 

 granular, save in the centre, where it is more liquid. The 

 nucleoli are found in the parietal layer. When the nucleus 

 divides there is first formed in its interior a plasmatic 

 portion, then the two halves swell and become isolated by 

 prolongation of the dividing fissure. In some cases the 

 two nuclei remain adpressed. 



Part II. — Special Researches. 



The following examination was by longitudinal sections 

 of the stem or sometimes of the petiole, eosin (a solution 

 in spirit) being the staining fluid commonly used. 



* Bot. Zic/., x.xxviii. (1880;, pp. 845-8.')4 (pi. sii. figs. 1-22). 

 t Comptcs P^P<i7/x. xcii. asSl). pp. 147-?. 



