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POPULAR SCIENCE REVIEW. 
to use it as a dye, it could be obtained in large quantities, and would thus 
give an occupation to many hands unfit for heavier labour. 
The Real Nature of Fsorospermioe. — These beings, which are usually 
parasitic on fresh-water fishes, and which were ranked by Leydig and 
others among the Gregarinidse, have been placed by M. Balbiani in the 
vegetable kingdom. This distinguished naturalist has observed in the 
cavity of the transparent shell of these organisms, and towards one of its 
extremities, two little vesicular pyriform organs. At the point of union 
of these bodies the shell of the psorosperm is pierced by an aperture, which 
forms a communication between its cavity and the external medium. 
The walls of these vesicles are thick and granular, and within them may 
be seen a filament coiled up spirally and filling the entire cavity. These 
filaments are not at first easily observed, but on adding caustic potash they 
are seen to project as two delicate leashes. The filament is usually four 
times, but sometimes even ten times as long as the entire animal, and is 
often so attenuate at its extremity as to escape detection. M. Balbiani 
supposes that these filaments perform the same function in these beings as 
the antherozoids of other cryptogams. Moreover, there exists also in the 
general cavity of the psorosperm a glutinous mass or nucleus which dis- 
engages itself in propagation, and is nothing more nor less than a vegetable 
spore. [This relation of the Psorospermise to plants has been also 
suggested by Dr. Spencer Cobbold, in the Intellectual Observer for April, 
1862. — Ed. Popular Science Review.] 
Distribution of Infusoria . — With a view to determine the species of 
Infusoria prevalent in the atmosphere of various countries, Mr. J. Samuelson 
examined the dust from rags which had been brought from Alexandria, 
Trieste, Tunis, Peru, and Melbourne. His investigations have led him to 
conclude — 1st, that the atmosphere in all parts of the globe contains cor- 
puscles belonging to the animal, vegetable, and mineral kingdoms ; 2nd, 
the Infusoria present are chiefly germs of monads, vibrios, and kolpodas ; 
3rd, these organisms are more abundant in a dry than in a moist atmo- 
sphere ; 4th, the tenacity of life exhibited by these germs is far greater 
than some observers seem to think. The author concludes with some 
remarks tending to show the untenability of the spontaneous-ge neration 
doctrines. — Comptes Rendus , LVII. 87. 
The Air in the Swim-bladder of Fish. — M. Moreau analysed the air 
contained in this organ, and found it to consist of oxygen, nitrogen, 
and carbonic acid in proportions varying with the species and even with 
the individual. To ascertain the cause of these variations, he caused a 
certain number of the common perch (Perea fluviatilis) to be asphyxiated 
by immersion in water from which air had been excluded ; and he 
destroyed an equal number of active fish by dividing their spinal chords ; 
lie then proceeded to analyze the gases contained in the bladders of both 
series ; and he found in the first, that the quantity of oxygen present 
did not exceed 3GG per cent., whilst that of the second amounted to 19'25 
in a hundred parts. lie considers then : “ That the proportion of oxygen 
contained in the swim-bladder of the perch diminishes to zero when the 
fish is so circumstanced that it cannot abstract this element from the 
surrounding medium.” 
