110 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of the cell. This central portion shows, in proportion to its density, 

 the reactions of the pyrcnoids of other algae. A siniihxr form of 

 chromatophore is characteristic of E. geniculala ; and from this there 

 are transitions to the form found in other species of Ew/lena and 

 Phacus, in which they occur as small flat disks with rounded corners, 

 resembling those of Vascular Cryptogams and Phanerogams. In E. 

 viridls and E. (jeniculnta tlie entire mass of paramylnm is composed of 

 two kinds of grain, one kind developed along the surface of the 

 central piece of the chromatophore, the other along the outer surface 

 of the ribbon-shaped prolongations of the chromatophore. 



The paramylura-grains of the Euglenea3 appear to originate in the 

 chromatophore, and to increase in size by the continuous apposition 

 of new substances derived from it. Schmitz's researches have shown 

 the chemical and physical properties of paramylum to resemble those 

 of normal starch much more closely than had previously been 

 supposed. 



Similar observations on Flagcllatfe which do not contain chloro- 

 jihyll, such as the genera Astasia, lihahdomonas, and Monoidetim, 

 show that here the starch- and paramylum-grains are formed directly 

 out of the colourless protoplasm of the cell. 



Observations on fresh-water diatoms, FrustuUa saxonica, Cymhella 

 cipnhiformis, &c., showed that in these also the pyrenoids are always 

 formed, as in Euglena, &c., in the interior of the substance of the 

 chromatophores, and are never stored up outside them. 



With regard to the finer structure of chromatophores, F. Schmitz 

 thinks that we are not yet in a position positively to answer the question 

 whether they have a reticulate framework, or whether small dense 

 granules or drops are imbedded in a continuous matrix, or to state in 

 what way the green or red colouring matter is distributed. He him- 

 self favours the idea that the colouring substance completely permeates 

 the fibrillfe of the framework. But these points cannot be said to be 

 at present determined by direct microscopical observation. 



G. Klebs * contests the statement of Schmitz with regard to the 

 origin of the paramylum-grains in the Eugleneae. He states that 

 there is never any direct connection between them and the chromato- 

 phores ; but that, on the contrary, the paramylum always originates in 

 the cytoplasm, there being some Euglenece in which the chromato- 

 phores are entirely wanting. In the finer structure of the paramylimi- 

 grains, Klebs maintains also the existence of a concentric lamination, 

 which can be made evident by mechanical pressure, or by treatment 

 with swelling reagents ; and the same is the case also with the radial 

 striation of the chromatophores of Euglenesc. 



Development of Bacteria.f — G. Wigand maintains the develop- 

 ment of bacteria by spontaneous generation from protoplasmic sub- 

 stances themselves without any pre-existent germs. Processes of 

 decay consist essentially of two distinct stages : (1) the stage of 

 maceration or morphological disintegration, in which the organized 



* Bot. Ztg., xlii. (1884) pp. 566-73. 



t Wigand, G., ' Entsehung u. Fermentwirkung dcr Bakterien,' 40 pp., 

 Marburg, 1884. See Bot. Centralhl, xix. (1884) p. 359. 



