Page:Popular Science Monthly Volume 10.djvu/782

762 anæmia. A student in St. Thomas's Hospital volunteered to supply the blood for the operation. The patient received 200 grammes of blood without showing any bad symptoms; he even gave evidence of being roused from his habitual torpor. Three hours after the operation, the patient, who had, in the mean time, been placed in a warm bed, and had taken doses of tea and brandy, had a full pulse, rate 90, respiration 28. He answered to his name and spoke a few words, rubbed his face with one of his hands, opened his eyes, and swallowed voluntarily. Five hours later the pulse was 100, strong, respiration 30. The following day the pulse was 96 and respiration 28, and the patient ate and drank well and often. Toward evening the pulse was 90, respiration 28, and he spoke and answered slowly when spoken to; said he had no pain. Four days later the symptoms still continued to be favorable. The process of transfusion was to be repeated by the physicians, the results being so encouraging.

Production of Sulphurous Acid for Use as a Disinfectant.—Sulphur-fumes (sulphurous acid) have from time immemorial been employed to fumigate and purify infected air, but the ordinary method of producing the fumes by burning sulphur is cumbrous and very uncertain. Mr. T. W. Keates offers in the Lancet a ready and simple means of effecting this object. Instead of sulphur, he proposes to use bisulphide of carbon, a compound consisting of two atoms of sulphur and one of carbon. It is a dense, mobile liquid, heavier than water, and intensely inflammable. During combustion the constituents of the bisulphide combine with the oxygen of the air, producing sulphurous and carbonic-acid gases, the former greatly exceeding the latter in quantity. The bisulphide can be burned in a common spirit-lamp, or it may be mixed with oils and burned in an oil or kerosene lamp. Any proportionate quantity of sulphurous acid can in this way be thrown into an atmosphere, and the action may be continued for any length of time. As bisulphide of carbon is extremely volatile, the lamp should be furnished with a well-fitting screw-cap, to prevent loss by evaporation.

A Fishing-Spider.—"Just before the late war," writes the author of a communication in the American Naturalist, "I was at Colonel Oakley Bynum's spring, in Lawrence County, Alabama, near the town of Courtland, where I saw a school of minnows playing in the sunshine near the edge of the water. All at once, a spider, as large as the end of my finger, dropped down among them from a tree hanging over the spring. The spider seized one of the minnows near the head. The fish thus seized was about three inches long. As soon as it was seized by its captor, it swam round swiftly in the water, and frequently dived to the bottom, yet the spider held on to it; finally, it came to the top, turned upon its back, and died. It seemed to have been bitten or wounded on the back of the neck near where the head joins. When the fish was dead, the spider moved off with it to the shore. The limb of the tree from which the spider must have fallen was between ten and fifteen feet above the water. Its success shows that it had the judgment of a practical engineer."

Qualitative Determination of Potassa.—Carnot offers a new and simple process for the qualitative detection and the determination of potassa, hitherto one of the most delicate operations in analytical chemistry. It is as follows: In a few drops of hydrochloric acid, one part of the subnitrate of bismuth, say half a gramme, is dissolved, and then, in a few cubic centimetres of water, are dissolved about two parts (one gramme to one and a quarter) of crystallized hyposulphite of soda. The second solution is poured into the first, and concentrated alcohol added in large excess. This mixture is the reagent. If brought in contact with a few drops of the solution of a potash salt, it at once gives a yellow precipitate. With an undissolved potassic salt it produces a decidedly yellow coloration, easily recognized. All potassic salts with mineral acids are susceptible of this reaction; it is also very sensitive with the organic salts—tartrates, citrates, etc. The reaction is not interfered with by the presence of other bases, with which nothing analogous is produced. The character is therefore perfectly distinct. Baryta and