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THE POPULAR SCIENCE MONTHLY. 



anaemia. A student in St. Thomas's Hos- 

 pital 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 be- 

 ing roused from his habitual torpor. Three 

 hours after the operation, the patient, who 1 

 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, respira- 

 tion 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 symp- 

 toms still continued to be favorable. The 

 process of transfusion was to be repeated 

 by the physicians, the results being so en- 



Prodnction of Solpharons Acid for Use 

 as a Disinfectant. Sulphur-fumes (sulphur- 

 ous 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 of- 

 fers 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 sul- 

 phur and one of carbon. It is a dense, mo- 

 bile liquid, heavier than water, aHH intensely 

 inflammable. During combustion the con- 

 stituents 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 bi- 

 sulphide 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 atmos- 

 phere, and the action may be continued for 

 any length of time. As bisulphide of car- 

 bon 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 communi- 

 cation in the American Naturalist, " I was 

 at Colonel Oakley Bynum's spring, in Law- 

 rence County, Alabama, near the town of 

 Courtland, where I saw a school of min- 

 nows 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 determi- 

 nation of potassa, hitherto one of the most 

 delicate operations in analytical chemistry. 

 It is as follows : In a few drops of hydro- 

 chloric 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 crystal- 

 lized hyposulphite of soda. The second 

 solution is poured into the first, and con- 

 centrated 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 pre- 

 cipitate. With an undissolved potassic salt 

 it produces a decidedly yellow coloration, 

 easily recognized. All potassic salts with 

 mineral acids are susceptible of this reac- 

 tion ; it is also very sensitive with the or- 

 ganic salts tartrates, citrates, etc. The 

 reaction is not interfered with by the pres- 

 ence of other bases, with which nothing 

 analogous is produced. The character is 

 therefore perfectly distinct. Baryta and 



