250 THE NORTHERN MICROSCOPIST. 
with spherical cells, about t-1200th part of an inch in diameter ; 
cells with a distinct membrane, their contents consisting of 
numerous tolerably equal granules, red or green. Between the 
large cells lie patches of minute red granules, apparently dis- 
charged from the large cells. Bauer and Greville both describe 
this as the mode of propagation of the plant; but it is probable 
that the cells also increase by division when actively vegetating.” 
In a very pleasant little book called ‘Footprints from the Page 
of Nature’ I find the following: “If we place a portion of the 
snow coloured with this plant upon a piece of white paper and 
allow it to melt and evaporate, we find a residuum of granules 
just sufficient to give a faint crimson tinge to the paper. Placed 
under the microscope, these granules resolve themselves into sphe- 
rical purple cells, from the 1,o0oth to the 3,co0th part of an inch 
in diameter; each of these cells has an opening surrounded by 
serrated or indented lines, whose smallest diameter measures only 
the 1-5,oooth part of an inch.” 
The same author says, further on: “The actinic power of the 
solar light, aided by some peculiar, and as yet unknown property 
belonging to the natural whiteness of the snow itself, is highly 
essential in the production of the beautiful crimson or rose colour 
by which the red snow is distinguished ; but this colour gradually 
changes to green when secluded from the direct action of light 
and developed on dark or opaque objects.” 
Although the above is, as I have said, the generally accepted 
theory of red snow, yet examinations of red snow made near 
Grimsel, in Switzerland, in 1839, at the Glacier of Aar, in 1840, 
and other places, led Mr. Shuttleworth and Professor Agassiz® to 
conclude that the discolouration was due to an immense number of 
moving animalcules of various shapes and sizes, and to globules 
which were supposed to be the ova of Philodina roseola. 
Professor Meyent remarks that Euglena sanguinea and Euglena 
viridis, which greatly resemble Protococcus,t are the cause of the 
red and green snow which has been described by Martius, a 
naturalist, who had accompanied a French expedition to Spitzber- 
gen. In this case also globules are mentioned. 
From these researches it is evident that it is not proved that red 
snow is dependent on one form of organic existence, but that 
many species both of plants and animals may contribute to its 
production, 
Having thus briefly noticed all that I can discover about red 
snow, I will give a short account of some that I found on the 28th 
soma at 
* ‘Ann, Nat. Hist.,’ Aug., 1841. + Ann, Nat. Hist.,’ Aug., 1848. 
+ See Cohn’s Memoir “On the Natural History of Protococcus pluvialis” in 
‘ Botanical and Physiological Memoirs’ (Ray Souety, 1853). 


