96 



CHEMISTRY. 



the summer months of 1881, without any one 

 suspecting the presence of anything unusual. 



Remarkable antiseptic properties have been 

 discovered in peroxide of hydrogen by MM. 

 Paul Bert and P. Kegnard. It immediately 

 and definitely arrests all fermentation due to 

 an organized ferment, and kills the ferment, BO 

 that the fermentation does not recommence, 

 even after the removal of the hydrogen perox- 

 ide by one of the substances that destroy it 

 most rapidly. It also arrests the putrefaction 

 of all substances which do not decompose it. 

 At the same time, it has no effect on diastase 

 fermentations, and the gastric and pancreatic 

 fluids continue to act in solutions containing 

 it. MM. Bert and Regnard further announce, 

 as results of their investigations, that dilute 

 hydrogen peroxide is not destroyed by fats, 

 starches, soluble ferments, egg-albumen, casein, 

 the peptones, creatine, creatinine, or urea; it is 

 rapidly destroyed by nitrogenous collagens, by 

 musculin, fibrin of the blood, and various nitro- 

 genous vegetable matters ; and that this action 

 is definitely arrested by a temperature above 

 TO 0. (140 Fahr.). Putrefaction, however, 

 leaves the peroxide entirely intact. Acting 

 upon the suggestions of these investigations, 

 MM. Pean and Baldy, of the Hospital St. Louis, 

 have used the peroxide as an antiseptic in sur- 

 gery, with very successful results. They find 

 that, when containing from two to six times 

 its volume of oxygen, it appears to be capable 

 of advantageously replacing alcohol and car- 

 bolic acid. It can be employed externally, for 

 the dressing of wounds and ulcerations of all 

 natures, in injections and in vaporization, and 

 internally. Satisfactory results have been ob- 

 tained from its use in old wounds as well as 

 fresh ones; and the general as well as local 

 state appears to be favorably influenced by it. 

 It has the advantage over carbolized water, of 

 being free from all poisonous effects and un- 

 pleasant odor, while its application is entirely 

 painless. Peroxide of hydrogen for surgical 

 use must be entirely neutral. That obtained 

 in commerce contains a considerable quantity 

 of sulphuric acid, and is therefore not wholly 

 safe. 



Dr. R. Koch having remarked that the only 

 substances worthy of the name of disinfectants 

 are chlorine, bromine, iodine, mercuric chlo- 

 ride, and perhaps potassium permanganate, and 

 having particularly disputed the antiseptic 

 properties of zinc chloride, Fr. Boillat calls 

 attention to the fact that for a substance to be 

 an antiseptic it is not necessary for it actually 

 to destroy the germs. In the antiseptic treat- 

 ment of wounds it would be impossible to em- 

 ploy such violently acting substances as those 

 mentioned by Koch. All that is necessary is 

 the presence of substances capable in some 

 way of restraining the development of the 

 gorms, and such substances may from that fact 

 properly be called antiseptics. Many antisep- 

 tics have the power of coagulating proteids. 

 Among these is zinc chloride, and Boillat found 



by experiments that coagula prepared with that 

 substance required from thirty-one to forty- 

 five days for bacteria to appear in them, while 

 in serum, gelatine, and phenol albuminates pre- 

 pared at the same time, the bacteria appeared 

 in one or two days. Applied to the surface of 

 a wound, zinc chloride forms a superficial coat- 

 ing of the neutral zinc albuminate, which af- 

 fords no means for the bacteria to develop, and 

 protects the parts under it. 



PETEOLEUM-TESTS. Engler and Haas have 

 thoroughly tested the different forms of ap- 

 paratus in use for the determination of the 

 flashing-point of petroleum, and find that all 

 those are worthless in which the determina- 

 tion is made indirectly by measuring the ten- 

 sion of its vapor ; because the tension of the 

 vapor of petroleum and its inflammability 

 stand in no simple relations to each other. 

 Those tests in which the petroleum is heated 

 in an open vessel have also been found to give 

 unreliable results. Among these is the Say- 

 bolt tester, used in the United States, which 

 gives results that are too high. Many of those 

 testers in which the oil is heated in closed ves- 

 sels were found to be constructed on false 

 principles. The following principles have been 

 laid down as those which ought to be kept in 

 mind in testing petroleum, or in judging of the 

 efficiency of the testing apparatus : The quan- 

 tity of petroleum used in each case must be 

 the same, and for each separate test a fresh 

 portion must be taken. The heating must be 

 uniform and slow, and the heating period 

 should extend over 10 ; while those oils whose 

 flashing-point is but little above the tempera- 

 ture of the air should be cooled about 10 be- 

 fore heating. The intensity of the ignition 

 flame and its distance from the surface of the 

 oil must be the same in all the tests. If the size 

 of this flame be increased and its distance from 

 the oil be diminished, the flashing-point will 

 be lowered. The ignition flame must never be 

 so near the oil as to cause local vaporization, 

 and for this reason its time of action should be 

 reduced to a minimum. In general, the con- 

 ditions for the formation of combustible gases 

 in the testing apparatus should resemble as 

 nearly as possible those which occur in lamps 

 or in petroleum-stoves. Victor Meyer's method, 

 in which a closed cylinder, one fifth filled with 

 oil, is heated in a water-bath to a desired tem- 

 perature, and is then taken out and shaken vio- 

 lently and tested with a gas-jet, was found to 

 possess the advantages claimed by its author, 

 and to give a fairly accurate test. Abel's test, 

 adopted by the English and German Govern- 

 ments, employs an air-bath inclosed by a 

 water-bath, to" insure a slow heating of the oil, 

 and may be tried and read at any time by 

 merely opening the lid of the vessel. Its values 

 are, however, regarded as too low. Skalneit 

 has suggested that the specific gravity, the 

 boiling-point, and the index of refraction of 

 petroleum, be used in judging of its quality ; 

 but Engler and Haas have arrived at the con- 



