248 Phillips on a Comparative Study of the 
ent in all cells. A portion of the central body he found to 
be soluble in artificial gastric juice, the insoluble portion 
being composed of two substances, one related to plastin, 
which was always present, and the other, which he called 
“central substance,” was allied to nuclein of higher plants. 
This might be absent, especially in dividing cells where it 
seemed to disappear. In discussing the relationships of the 
“central substance” to the nuclei of higher plants, he con- 
cluded that it differed in all respects from a true nucleus, 
basing his inferences, among other reasons, principally on 
the following two foundations: (a) Nuclein might or 
might not be present in all of the cells of the Cyanophycee, 
or it might be present in some and absent from other cells of 
the same trichome; (b) Nuclein disappeared entirely from 
the dividing cells of the Cyanophycez, while division in the 
higher plants was always preceded by an increase in the 
amount of chromatin. He was of the opinion that the 
absence of sexuality in these organisms was related in some 
way to the absence of a nucleus. Zacharias called the slime 
balls of Schmitz “grains,” and could not identify them as 
paramylum or as a gelatinous substance, but after exhaus- 
tive micro-chemical studies he concluded that they were of 
a carbohydrate nature. In division he described a collar- 
like ingrowth which constricted the cell into halves, but he 
could find no evidence of karyokinetic figures. After con- 
tinued cultivation of the Cyanophycez in his laboratory, he 
observed that the ‘“‘central substance” or so-called “nucleus” 
became smaller and finally disappeared, and would again as 
mysteriously reappear. He could not account for this 
behavior. 
In another paper (91) called forth by the works of Hier- 
onymus and Zukal, Zacharias reaffirmed his results as out- 
lined in his work of 1890. In regard to a chromatophore, he 
found, in properly prepared living Scytonema, a peripheral 
plasma pierced by minute pores. Small colored bodies 
seemed to be imbedded in the cytoplasm which surrounded 
