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 Cyanophyceae, 

 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 Cyanophyceas, 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 Cyanophycec-e 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 



