SiGERSON — On the Atmosphere. 
15 
and blueish starch, and with a considerable number of Protococcus 
nivalis, a beautifully green plant. 
In the lungs and air-vessels of city birds he found ctarch granules, 
and soot, and fragments of clothing ; in country animals, only debris 
of plants and pollen. In the lungs of a man and a woman who had 
died in an hospital, he came upon a notable quantity of starch granules, 
both normal and panified; fragments of flint and glass, of a red- 
coloured wood, of clothing ; and, lastly, the living larva of one of the 
arachnida, 
" In all our experiments," he adds, which, without exaggeration, 
may be reckoned by hundreds, we have never encountered either a 
solitary spore, an egg of lower animal, nor an encysted animalcule." 
Hermann Hoffman, on gooseberries, found some traces resembling 
the yeast and spores of Cladosporium and of Stemphylium. On the 
other hand, Ehrenberg, Burdach, Baer, Hensche, Wagner, and Leuckart 
failed, like Pouchet, to find either ovum or spore in the atmosphere, 
Joly, Musset, and Baudrimont declare they are extremely scanty. 
''Until now," wrote the latter from Bourdeaux, " I have not found in the 
air we breathe those monsters and fantastic creatures wherewith the 
imagination of man has peopled it.'' SchaafFhausen, Professor at Bonn, 
remarked that ''one would seek in vain for ova subsiding from the 
atmosphere in open vessels, used for experiments." With reference to 
spontaneous generation, Bechi, in studying the dew of the Maremmas 
of Tuscany, found no trace of the reproductive bodies of animals or 
plants. M. Pasteur, on the contrary, with some adherents, believes that 
the atmosphere abounds in germs, though some tracts of it may be 
barren. 
One practical result of this discussion was, that Dr. Eiselt, of 
Prague, investigated the atmosphere of his hospital, and found particles 
of contagious ophthalmia, then an epidemic. 
With the discussion of the question of spontaneous generation I have 
here nothing to do. The contents of the atmosphere were chiefly inte- 
resting to me, inasmuch as they afl'ected health. 
On the accompanying Plates are represented the results of my 
investigations of — 1st. " The Sea Breeze" (Plate IV.) ; 2nd. " Country 
Air" (Plate Y.) ; 3rd. " City Air" (Plates VI. and VIL). 
The Sea Breeze. — Glass, on being exposed to the influence of the sea 
air, was found to become quickly tarnished. On making a microscopi- 
cal examination of this, the cause was readily found. Crystals innu- 
merable were seen deposited upon it, most of which, on account of 
their shape and the circumstances, were recognised at once as crystals 
of chloride of sodium, or common salt. Some were deposited in minute 
drops of water, where they increased in number by the formation of 
new crystals ; some were deposited already crystallized and in a dry 
condition, like hailstones. The moisture is taken up from the waves 
by the wind in its course over them ; and, whilst so suspended in the 
air, favoured by its agitation, the crystals are frequently formed. 
Having used several object-glasses, with intent to secure accuracy, 
