286 Phillips on a Comparative Study of the 



cause of this lack and its division by direct methods, he 

 conckided that the central body was not likely a nucleus, 

 though it might have had a common origin with that organ. 

 Hegler, on the other hand, was able to find all stages of 

 mitotic division in the central body and strongly affirmed 

 its nuclear nature. Scott and Dangeard also recorded the 

 mitotic division of the central body and its consequent 

 nuclear character. Chodat and Malinesco did not consider 

 the central body to be a nucleus, and later Chodat, publish- 

 ing conjointly with Short, described the central body as a 

 vacuolated portion of the cell contents, laden with slime 

 balls. 



Thus the views concerning the central body of the Cyano- 

 phyceae differed. Some attributed to it a nuclear nature 

 with mitotic divisions. Others considered it a nucleus, but 

 with direct divisions. Still others regarded it as not a 

 nucleus, but the phylogenetic progenitor of one, or that it 

 originated from a common organ with the nucleus of higher 

 plants though itself not representing that organ, while some 

 looked upon the central body of these organisms as in no 

 sense a nucleus or even functioning as such, even calling 

 it a collection of vacuoles or, in one case, the cytoplasm. 

 Whether the central body should be termed a cell nucleus 

 depends entirely upon our definition of that organ. If our 

 conception of nucleus is that it must have all the attributes 

 of nuclear membrane, reticulum and nuclear sap, nucleolus, 

 etc., as in the higher plants, together with a definite form, 

 then this central body does not fulfill the requirements of the 

 definition. But if we consider a nucleus to be a centre in 

 which is located the hereditary material of the plant, and 

 which governs the constructive activities of the cells, such 

 as assimilation, growth and repair, also reproduction of 

 form or structure, if in other words, we consider the nucleus 

 from the physiologico-morphological side, then there can be 

 no reason for denying the nuclear nature of the central body. 

 Even measured by the first requirement above mentioned 



