Page:Popular Science Monthly Volume 16.djvu/742

 a breathing-tube of an inch bore proceeding downward, is firmly tied over the mouth and nose. Dr. Richardson carefully observed two experiments, one of twenty minutes' length, and another of an hour; and was assured by the diver that when under water he breathed as freely and easily as in the air. This was confirmed by his appearance and condition at the end of the longest experiment. He moved about on the floor of the tank, picked up coins, and could lie down and get up without difficulty. The exact mode by which breathing is effected Mr. Fleuss declares to be extremely simple, though it still remains a secret, but it is wholly carried on within the apparatus, not even the expired air becoming apparent in the water. The facts demonstrate that, without assistance from above, a man who has had no previous experience of diving or remaining under water can take down with him sufficient oxygen to live there easily for an hour; and but for the cold the diver asserted that he could have remained another hour and a quarter, and that he could easily arrange to remain four hours. Depth he said would make no difference as to breathing within the apparatus. Dr. Richardson is enthusiastic over the practical possibilities of the discovery. If a man can thus take his stock of breathing material with him, and live for hours without external access of air, he may extend the field of his industries and investigations into the deep sea, or the most rarefied atmospheres, into mines filled with choke-damp, or amid the suffocating smoke of conflagrations, without fear of consequences.

Suicide of the Scorpion.—The following facts, as stated by Mr. Allen Thomson in "Nature," throw some light on the mooted question of the self-destruction of scorpions. He states that while residing at Lucca, in Italy, he was greatly annoyed by the intrusion into the house of small black scorpions, which secreted themselves in bed clothing and articles of dress. Having been informed by the natives that this animal would destroy itself if exposed to a sudden light, attempts were made to dispose of the pest in the manner suggested. When one was caught it was accordingly confined under an inverted glass until evening, when the light of a candle was brought near it. At this, the scorpion showed great excitement, rushing round the glass with reckless speed. This state lasted for a minute or two, when the animal suddenly became quiet, and turning his tail over its back brought the recurved sting down upon the middle of its head. Soon it became motionless, and in fact dead.

Electricity and Vegetation.—Several months ago M. Grandeau and M. Leclerc described to the Paris Academy experiments on the influence of electricity on vegetation. From these it appeared that flowering and fructification are retarded whenever plants are excluded from this agent. Recently M. Naudin has been examining the subject, repeating the experiments of Grandeau and Leclerc under different circumstances, and with widely different results. He regards the question as a complex one, and far from being yet settled. The influence of electricity on plants is probably modified by the species, by climate, season, temperature, dry or wet weather, degree of light; possibly, also, by the geological and mineralogical structure of the ground. Until we are better acquainted with these obscure conditions of the problem, any conclusion applied to the whole of the vegetable kingdom is premature.

Transmissibility of Human Rabies.—Whether hydrophobia can be transmitted from man to man, or from man to the lower animals, has long been a disputed question, with little scientific evidence on either side; some recent observations, however, by M. Raynaud, in the Lariboisière Hospital, in Paris, would seem sufficiently conclusive to put an end to all uncertainty on the subject. A man was brought to the hospital suffering from rabies, having been bitten by a dog on the lip forty days before. The wound was cauterized two hours after it was made, and no serious apprehensions were felt about the result until a few days before he entered the hospital, when the usual symptoms of hydrophobia appeared. The day before his death, in a quiet interval, he yielded with the best grace to experiments in inoculation which were made with his blood and his saliva. The result