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THE POPULAR SCIENCE MONTHLY. 



Local Temperatures of the Blood. 



From researches made by Claude Bernard, 

 it appears that while the temperature of 

 the blood in the aorta and its more impor- 

 tant branches is uniform, that of the venous 

 blood varies considerably in different re- 

 gions of the inferior vena cava and its prin- 

 cipal tributaries. At the junction of the ex- 

 tremities and the neck with the trunk of 

 the body, the venous blood is colder than 

 that iu the great arteries ; in the right heart 

 it is considerably hotter. If we determine 

 its temperature at successive points in the 

 inferior cava, we find that at the junction 

 of the iliac veins this is lower than the ar- 

 terial temperature : on a level with the en- 

 trance of the renal veins, the two are about 

 equal ; on a level with the hepatic veins, 

 the temperature of the venous exceeds that 

 of the arterial blood by nine-tenths of a 

 degree. It retains this superiority even 

 after it has become mixed in the right heart 

 with the colder blood returned through the 

 superior cava. Accordingly, though the 

 venous blood of the peripheral parts is 

 colder than in the arteries, it acquires suffi- 

 cient heat during its passage through the 

 abdominal cavity, not merely to equalize 

 the difference, but actually to give it a per- 

 manent advantage. This is so, not because 

 the viscera are the source of animal heat, 

 but simply because they are by their situ- 

 ation protected from the effects of radiation 

 and evaporation. Heat is generated in all 

 the tissues, muscles, nerves, nerve-centres, 

 and glands. The rise of temperature, which 

 may always be detected in a muscle when 

 thrown into a state of contraction, is in- 

 variably preceded by a slight depression ; 

 and precisely the same phenomenon is ex- 

 hibited by a gland when its secretory nerve 

 is stimulated. 



Electro-Plating. We take from Tan 

 Nostrand's Engineering Magazine the fol- 

 lowing statement of the results obtained by 

 Bertram! in experiments in electro-plating 

 with aluminium, magnesium, cadmium, bis- 

 muth, antimony, and palladium. Alumin- 

 ium was deposited on decomposing, with a 

 strong battery a solution of the double 

 chloride of aluminium and ammonium; a 

 plate of copper forming the negative pole 

 whitens gradually, and becomes covered 



with a layer of aluminium, which takes a 

 good polish. The double chloride of mag- 

 nesium and ammonium in an aqueous solu- 

 tion is readily decomposed by the battery, 

 giving in a few minutes strongly-adherent 

 and homogeneous deposits of magnesium 

 on a sheet of copper. It polishes readily. 

 The battery must be powerful. Cadmium is 

 best deposited from the bromide to which 

 a little sulphuric acid has been added ; it 

 is then very coherent and very white, and 

 takes a fine polish. The sulphate, if acid- 

 ulated, also gives an immediate deposit of 

 metallic cadmium, very adhesive and capa- 

 ble of a good polish. Bismuth is deposited 

 from a solution of the double chloride of 

 bismuth and ammonium on copper or brass . 

 by the current from a Bunsen element ; it 

 is very adhesive, and might be used in dec- 

 orating works of art. Antimony can be 

 deposited from a solution of the double 

 chloride of antimony and ammonium at 

 common temperatures. Deposits of palla- 

 dium are obtained with ease by means of 

 the double chloride of palladium and am- 

 monium, either with or without the battery. 

 The solution must be perfectly neutral. 



New Method of Artificial Respiration. 



Dr. Benjamin Howard, late of the Long Isl- 

 and Medical College, recently gave at King's 

 College Hospital, London, a demonstration 

 of liis "direct method" of producing arti- 

 ficial respiration. For the purpose of mak- 

 ing his description of the method perfectly 

 plain, Dr. Howard had a man to act the part 

 of a person rescued from the water, and 

 apparently dead from drowning. The first 

 thing done was to rip away the wet clothing 

 to the waist, making of it a large, firm bol- 

 ster. "Quickly turning the face down- 

 ward," said he, as he proceeded to explain 

 the process, " the bolster beneath the epi- 

 gastrium, making that the highest point, 

 the mouth the lowest ; placing both hands 

 on his back immediately above the bolster, 

 my whole weight is thrown forcibly forward, 

 compressing the stomach and lower part of 

 the chest between my hands and the bolster 

 for a few seconds, two or three times, with 

 very short intervals." Thus the lungs are 

 relieved of water and the stomach emptied. 

 Then " quickly turn the patient on his back, 

 the bolster again making the epigastrium 



