BB Dr. E. Cohn on the Development and Propagaiion 



the chambers separated, and the whole contents were broken up 

 into a large number of free globular masses, which were sliarply 

 defined, composed chiefly of' colourless mucilage, and enclosed 

 in their centre an irregularly diffused, mostly laterally situated 

 heap of chlorophyll. These masses, the young spores, then pass 

 uninterruptedly through the most wonderful changes ; at first 

 they are in contact, and thus form by their adjacent boundaries 

 the plasmic septa, w^hich are consequently double; their sub- 

 stance becoming somewhat contracted, the two layers of these 

 septa separate, the spores thereby becoming isolated; the chlo- 

 rophyll in their interior is constantly changing its mode of dis- 

 tribution ; the colourless mucilaginous envelope at one time con- 

 tracts strongly, so that free, regular globules are produced ; at 

 fmother it expands again, so that they are flattened against their 

 neighbours ; or sometimes one becomes elongated laterally, and 

 if a drawing is begun to be made, its shape has entirely altered 

 before the sketch is completed. Finally, the nascent spores 

 become rounded-off into suiooth spheres, which however are 

 still far larger than in the mature condition, and are not com- 

 pletely filled with chlorophyll. But the latter becomes diffused 

 gradually more regularly in the spore-globe, while the colour- 

 less plasma is progressively more elaborated and excreted; 

 consequently the spore is constantly becoming more condensed 

 and diminished in size, and finally becomes a regular sphere 

 composed entirely of a granular green substance, enclosing a few 

 starch-granules, bounded externally by a smooth, clearly-defined 

 layer of plasma; there is no cellulose membrane, the green 

 structure is very soft, elastic, and under pressure passes away 

 into mucus ; it is to be regarded as a * primordial cell.' 



Long before the cofitents of the cells of Sphceroplea have be- 

 come converted into young spores, peculiar changes have com- 

 menced in the membrane of their cells; it begins to change into 

 amyloid, and therefore is now coloured purple-red or violet by 

 iodine alone, without sulphuric acid. Evidently this is the 

 commencement of the chemical metamorphosis of this mem- 

 brane, which terminates in its total solution and sets free the ripe 

 spores. At particular points of the membrane small holes are 

 formed j^^ to ^~ of a line in diameter ; I have counted from 

 two to six of these orifices in each cell ; the holes are more easily 

 observed, as colourless spots, when the cell is coloured blue by 

 sulphuric acid and iodine. 



This course of development, by which they are transformed 

 into sporangia with numerous spores, does not occur in all the 

 cells of a filament of Spjkjproplea ; during the same epoch totally 

 different processes are completed in a large portion of the cells. 

 Here the green rings between the colourless vacuoles have gra- 



