Cytology and Movements of the Cyanophycece. 289 



controlling centre of cell activity (86). What, then, if they 

 have no nucleus, can act as the governing agent in these 

 lower plants? Strasburger's experiments seem to prove 

 that proteids are formed only by the nucleus. If the Cyano- 

 phycese have no nucleus, what, we may say, forms the pro- 

 teids which are demonstrable in their cell contents? These 

 considerations would lead, a priori, to the conviction that 

 there must be a nucleus present in these so-called non- 

 nucleated organisms, or at least something that performs 

 the functions of one, if we are to accept the great bulk of 

 work done on many lines by cytologists. Whether this con- 

 trolling structure in the Cyanophyceas should be called a 

 nucleus, or by some other name, the organ functions as such, 

 and the difference is, evidently, a matter of the definition 

 of nucleus, and therefore a mere matter of words. The 

 localization of this controlling influence seems to be the 

 problem. If it should be found that here we have cells 

 exhibiting all of the properties of nutrition, growth, repro- 

 duction, heredity, etc., but devoid of chromatin in any form, 

 it would seem to weaken the conception of the nucleus above 

 referred to. But the investigations reported here show that 

 the Cyanophyceas are in no sense an exception to the scheme 

 of evolution, but in reality one of the earliest steps in the 

 phylogeny of the nucleus. 



The Chromatophore. 



Fischer was able, with hydrofluoric acid, to digest away 

 all of the protoplast except a hollow, barrel-shaped struc- 

 ture which contained the coloring matter. This he termed 

 the chromatophore. He therefore considered the Cyano- 

 phyceae to be without nuclei, but to have a color-bearing 

 organ. Biitschli, on the other hand, was able to digest only 

 the outer portion, while the central body was undigested, 

 and he thus drew the conclusion that nucleus and chroma- 

 tophore were both present. 



