INTRODUCTION TO CRYPTOGAMIC ROTANY. 115 



ture aud mode of propagation, are united under one common 

 name of Protococcus. One of the most familiar examples is 

 the P. cruentus, which is to be found at the northern base of 

 almost every wall, provided it be sufficiently damp, looking 

 as if venous blood or the sediment of port wine had been 

 poured upon the ground or stones. Such productions may 

 sometimes be the infant state of more complicated organisms, 

 but there is no reason to believe that such is the case in the 

 present instance, nor in several other similarly constituted 

 species. They are more or less gelatinous, in proportion as a 

 greater or less quantity of mucous matter is secreted from the 

 surface of the spores, or from the greater or less degree of 

 solubility of this matter ; but the gelatinous substance is by 

 no means to be considered as primary, or apj^roaching in any 

 respect to what the Germans call urschleim, a primitive jelly, 

 which they conceive to arise from chemical combinations, and 

 so in process of time to give rise by spontaneous generation to 

 reproductive globules. In some cases, it is not possible to see 

 the mode of propagation very clearly, in consequence of the 

 diminutive si^e, but wherever it is visible it seems always to 

 arise from division of the endochrome. At any rate, in the 

 red snow, Protococcus nivalis, we have a distinct and re^ieated 

 division of the endochrome into four, and attended by such 

 curious jDhasnomena, as to have made it a question whether it 

 belongs to the vegetable kingdom at all* The red snow has long 

 been the wonder of our Arctic voyagers, and travellers among 

 the Alps, but its curious characters do not admit of examination 

 from dried specimens merely. Fortunately a similar, if not the 

 very same production (Fig, 8, 9), grows abundantly in many ex- 

 posed situations, and living specimens have afforded Cohn and 

 others opportunity of study. In the very confines of the order, 

 we thus become acquainted with the striking resemblance which 

 is exhibited by certain states of Algaj and Infusoria: resem- 

 blances which are so close as to be perfectly convincing that 

 we must greatly modify om* notions of the distinctness of 



* Shuttleworlh sur la maticre coloraute de la ueige rouge. Bib], 

 Univ. de Geneve, Feb. 1840. 

 8 * 



