38 MOVEMENTS OF SIMPLE ORGANISMS. 



might suppose all vital functions would be extinguished. It was in the year 1760 

 that De Saussure first noticed that the snowfields on the mountains of Savoy were 

 tinged with red, and described the phenomenon as "red-snow." Once on the look-out 

 for it, people found this red-snow on the Alps of Switzerland, Tyrol, and the district 

 of Salzburg, on the Pyrenees, the Carpathians, and the northern parts of the Ural 

 Mountains, in arctic Scandinavia, and on the Sierra Nevada in California. But red- 

 snow has been seen on the most magnificent scale in Greenland. When Captain 

 John Ross in 1818 sailed round Cape York on his voyage of discovery to Arctic 

 America, he noticed that all the snow patches lying in the gorges and gullies of the 

 cliffs on the coast were coloured bright crimson; and the appearance was so start- 

 ling that Ross named that rocky sea-shore the "Crimson Cliffs." On the occasion of 

 later expeditions to the arctic regions, red-snow was observed off the north coast of 

 Spitzbergen, and in Russian Lapland and Eastern Siberia, but never in such sur- 

 prising luxuriance as on the Crimson Cliffs of Greenland. 



If a snow-field coloured by red-snow is examined near at hand it is found that 

 only the most superficial layer, about 50 millimeters in depth, is tinged. It is also 

 present in the greatest quantities in places where the snow has been temporarily 

 melted by the heat of summer, particularly therefore in depressions, whether big or 

 little, and towards the edges of the snow-field, where the so-called snow-dust or 

 Cryoconite extends regularly in the form of dark, graphitic smeary streaks. Exam- 

 ined under the microscope, the matter which causes the redness of the snow 

 appears as a number of spherical cells having a rather substantial colourless cell- 

 membrane and protoplasmic contents permeated by chlorophyll. The green colour 

 of the chlorophyll is, however, so disguised by a blood-red pigment that it is only 

 possible to detect it when the latter has been extracted, or in cases where it is 

 limited to a few definite spots in the cell. These spherical cells do not move, and 

 so long as the snow is frozen they show no sign of life. But as soon as the heat of 

 the summer months melts the snow, these cells acquire vitality, visibly increasing 

 in size and preparing for division and multiplication the moment they have 

 attained a certain volume. The growth, so far as it depends on nutrition, takes 

 place at the expense of carbon dioxide absorbed by the melted snow from the 

 atmosphere and of the inorganic and organic constituent parts of the dust. We 

 shall frequently have occasion to return to this dust, but at present it is only neces- 

 sary to observe, for the comprehension of the drawing of red-snow as seen under 

 the microscope (PI. I., figs, e-h), that in the Alps, amongst the organic materials 

 which constitute the dust, pollen-grains of conifers occur with great frequency, 

 especially those of the fir, arolla, and mountain pine. These pollen-grains have 

 been swept up into the high Alps by storms, and are already partially decayed. 

 In all the material that I investigated I found the red-snow cells mixed with 

 pollen-grains of the above-mentioned conifers. The pollen-grains are oval in cross- 

 section, of a dirty yellow colour, and swollen laterally into two hemispherical wings, 

 as is shown in PI. I., figs. e-h. 



As has been stated, the red cells are nourished by the constituent elements of 



