SOMATIC CHROMOSOMES IN VICIA 3og 



FiG. 39 probably represents a stage in which many nuclei pass the short 

 period of the interphase, since only a few are observed with a more uniform 

 reticubam. One or two nucleoli are invariably precent. Occasionally small 

 karyosomes are seen, but thèse are nearly always in nuclei advanced to a 

 State which in older tissue would be called the resting stage. 



Resting stage. 



In older tissue higher in the root where the divisions are taking place 

 very slowly or hâve ceased altogether the nuclei as a rule proceed farther 

 in their telophasic changes than do those of the rapidly dividing région. 

 FiG. 1 represents a nucleus from a long peripheral cell in which the cyto- 

 plasm forms only a thin pariétal layer. It is obvious from a considération 

 of the gênerai arrangement ot the cytoplasm and the position of the nu- 

 cleus that this cell bas long since ceased dividing, and that the nucleus bas 

 been in the resting state for some time. Besides the nucleolus there are 

 several large karyosomes and a number of smaller ones hen-e and there in 

 the network. The clear area around the nucleolus in many préparations 

 seems without question to be due to imperfect fixation, for in cells where 

 the fixation is otherwise good there is usually no such area, in agreement 

 with Strasburger's (o5) results. The phenomenon indicates that whatever 

 connection there may be bet\veen nucleolus and reticuluni is very weak, 

 for the latter never séparâtes from the karyosomes, which are connected 

 with the network by strands oi ail thicknesses. 



Contrary to the results of Lundegardh the karyosomes do not seem 

 to be split, though the occasional approximation of two may give rise to 

 such an appearance. Since thèse bodies arise after the resting reticulum 

 has been formed it seems better to regard them not as a resuit of telopha- 

 sic transformation, but rather as a phenomenon of the resting stage, as 

 Lundegardh (12) states. They appear in connection with the chromatic 

 network and resemble the latter in staining quality. They thus seem to 

 represent an élaboration product of the processes actively going on during 

 rest, this product to go toward the formation of the prophasic chromosomes 

 in nuclei which will again divide. In nuclei which bave ceased division, 

 as in FIG. 1, they are to perform no évident function. 



The structure of the resting reticulum is of the first order of impor- 

 tance. At first sight it appears, fig. 1, to be a fairly uniform network, 



