458 C. C. MACKLIN. 



FRAGMENTATION. 



A note may here be made regarding a pathological change which 

 nuclei subjected to unfavorable conditions undergo, viz., frag- 

 mentation. This change consists in a breaking up and degenera- 

 tion of the nuclei. In cells which had grown for six days in 

 unchanged media, in which food and oxygen had become depleted 

 and metabolic products had accumulated (Fig. 26) and also in 

 cells growing in a medium to which a small amount of ethyl 

 alcohol had been added (Fig. 27), this form of degeneration was 

 seen. Multilobulation of the nucleus appeared to antecede the 

 actual breaking away of the parts. These latter were of different 

 shapes and sizes, often did not contain a nucleolus, and showed 

 no power of growth. The cytoplasm enveloping them did not 

 divide and apparently was incapable of increasing. 



In preparations containing forms of this kind no mitoses were 

 seen, and the phenomenon seemed to be quite different from 

 nuclear amitosis which occurred only in healthy cells. It is 

 believed, moreover, that the process of fragmentation has been 

 confused with that of amitosis, and it is possible that it is this 

 confusion which has accounted for certain well-known views 

 which regard amitosis as an evidence of degeneration. 



VITAL STAINS. 



Finally, a word as to certain so-called "vital stains." It was 

 hoped that gentian violet would prove to be of value in rendering 

 visible the minutice of the living cell during its vital changes, 

 since the results following the use of this dye recorded by Church- 

 man and Russell ('14) and Russell ('14) with cultures of frog 

 tissue were so encouraging. Unfortunately the dye proved toxic 

 to the tissues used in a dilution of I in 200,000, and, though the 

 nucleoli, nuclear membranes, certain granules and the cell borders 

 were brought into sharp relief this staining was always accom- 

 panied by cessation of vital phenomena, and the cells speedily 

 went into degeneration. 



Janus green, in a dilution of I in 80,000, was also toxic, and, 

 while it stained mitochondria specifically, yet these bodies soon 

 became granular and lost their characteristic appearance. Hence 

 neither of these dyes could be spoken of as acting "intravitam," 



