3oO LESTER W. SHARP 



of the finer parts. The small amount of acetic acid is to be noted in this 

 connection — only 0.068 "/o, or 0.24 parts acetic to i part chromic. For 

 double chromosomes at late prophase it is fairly good, as the halves stand 

 clearly apart from each other, p'ig. 23. Also the rapid destaining property 

 renders material fixed in this solution of some value for the study of the 

 structure of the chromosome. 



Since the conditions under which the roots grew were fairly uniform 

 the dail)' periodicity in the frequency of division was not well marked. At 

 any hour ail stages could be found. The best hours, however, seemed to be 

 at about noon and six p. m.; at the former hour the number of prophases 

 was very large, while in the evening telophases were présent in greater 

 abundance. 



DESCRIPTION. 



In this portion of the paper the rcsults of the writer's work on Ficia 

 will be presented with références necessary to properly relate them to the 

 work of others, the gênerai discussion of the main points being reserved 

 for the foUowing chapter. In order that the account of the telophasic trans- 

 formation of the chromosomes into the resting reticulum and the prophasic 

 condensation of the latter into chromosomes may be given without inter- 

 ruption the description will begin with the fuUy formed chromosomes as 

 they appear at the end of prophase. 



Late prophase and metaphase. 



As the chromosomes arrange themselves upon the spindle preparatory 

 to their anaphasic séparation their double nature is obvious. In some pré- 

 parations the two halves lie very close together and may be twisted some- 

 what about each other. as in fig. 22, while in others they lie farther apart 

 and show the présence of anastomoses with great clearness, fig. 23. In the 

 immediately preceding stages the halves are pressed tightly together, so 

 that thèse anastomoses seem to be due to the mutual adhérence at certain 

 places when the halves move apart after the disappearance of the nuclear 

 membrane. Very often some of the chromosomes show a transverse seg- 

 mentation, as has been described by many writers. 



The double chromosomes take their places on the spindle with the halves 



