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THE POPULAR SCIENCE MONTHLY 



sanitary agent. The French railway com- 

 panies have for some time used it as a wash 

 to cleanse their cattle-cars. In some coun- 

 tries it is employed as a remedy for certain 

 affections of animals, and as a prophylactic 

 against contagious diseases. These services, 

 important as they are, are surpassed by 

 those which this substance is made to render 

 in the preservation of food. The quantities 

 of the acid which are required for this pur- 

 pose are very minute, and no case of injury 

 to any person has been traced to it during 

 the six years in which it has been in in- 

 creasing use ; yet some physicians have ex- 

 pressed the apprehension lest the continuous 

 daily consumption of salicylized food may 

 eventually produce derangement in the sys- 

 tem. The subject deserves careful examina- 

 tion. 



M. G. Hayem, having studied the physi- 

 ological and medical effects of inhalations of 

 oxygen, reports that when taken regularly, 

 mingled with an indeterminate quantity of 

 common air, oxygen produces an energetic 

 stimulation of the nutritive faculties. It is 

 especially beneficial to chlorotic patients, in 

 whom it restores the appetite, stops vomit- 

 ing, revives the movement of assimilation, 

 and causes increase of weight. Inhalations 

 of oxygen form a useful auxiliary in the 

 treatment of chlorosis with iron, especially 

 when gastric troubles make the application 

 of this treatment more difficult. The in- 

 halations are especially characterized by the 

 control they exercise over vomiting, which 

 is often suspended after one or two appli- 

 cations. They have also been observed to 

 promote an increased elimination of urea. 



Mr. G. S. Johnson has effected the syn- 

 thesis of ammonia by passing a mixture of 

 hydrogen and pure nitrogen over spongy 

 platinum at a low red heat, when ammonia 

 was produced at the rate of 5 - 9 milligrammes 

 per hour. The experiment was varied in 

 different ways, under one of which ammonia 

 was produced at the rate of twenty-four, 

 under another of three, milligrammes per 

 hour, while in others none was produced. 

 From all the experiments, Mr. Johnson has 

 concluded that nitrogen, like phosphorus, 

 may exist in two states, active and inactive, 

 the latter being brought on by exposure to 

 heat. 



Catherine C. Hopley suggests in "Land 

 and Water" a new theory of the so-called 

 fascination of birds by snakes. It is that 

 the bird mistakes the snake's tongue, which 

 the animal keeps in constant motion, while 

 it otherwise remains perfectly still, for a 

 lively worm, ami gazes at it with the expec- 

 tation of making food of it. The idea was 

 suggest* '1 by observations at the Zoological 

 Gardens, where the birds were frequently 

 seen watching the tongues of the snakes. 



Attempts have been made in England, 

 applying the principle of the Bessemer proc- 

 ess, to facilitate the extraction of copper 

 from the sulphuret by blowing air into the 

 pyrites, in order to consume the sulphur and 

 make it at the same time a source of heat 

 for the continuance of the process of reduc- 

 tion. They have failed, because the bath 

 would lose its heat as soon as the sulphur 

 was consumed. The discovery has been 

 made in a factory at Lyons, France, that the 

 presence of a compound containing phos- 

 phorus will protract the continuance of the 

 required temperature till the process is com- 

 pleted. The order of the combustion ap- 

 pears to be, first of the sulphur, next of the 

 metallic impurities, lastly of the phospho- 

 rus. 



The French Minister of Public Instruc- 

 tion has appointed a commission on hygi- 

 ene of the eyes in schools, for the purpose 

 of investigating the influence of the material 

 conditions of the arrangement and furnish- 

 ings of the school-room the seats, desks, 

 position of the light, etc., on the progress of 

 myopia, and of looking for means of oppos- 

 ing them. Dr. Gavarret is president of the 

 committee, and Dr. Javal is one of the mem- 

 bers ; and, in order that questions of typog- 

 raphy may not be overlooked, it includes 

 two publishers and a printer. 



M. E. Bouchut has suggested the use 

 of the digestive juice, papaine, which we 

 have recently described, for the dissolution 

 and digestion of the false membranes of 

 diphtheria. He has, in his experiments, 

 seen a thick, resisting, and elastic false 

 membrane from the trachea which he had 

 placed in a tube with one third part cf the 

 juice of the papaya, dissolved in a few 

 hours when cold, and in a few minutes 

 when the tube was warmed. Since begin- 

 ning his studies on this subject he has 

 treated thirty-two cases of infants or adults, 

 two of which were very severe, and lost only 

 four. 



M. GLEr, a French physiologist, has, 

 from experiments made upon himself re- 

 specting the effect of attention and intel- 

 lectual work upon cerebral circulation, con- 

 firmed the results of M. Mosso and added 

 some new observations. De finds that the 

 rhythm of the heart suffers an acceleration 

 which is increased in a direct proportion 

 with the intensity of the attention. Thus 

 the pulse was quicker when he studied ge- 

 ometry than when he studied philosophy, 

 with which he was more at home. The 

 carotid artery is also dilated during cere- 

 bral work', and the earotidian pulse becomes 

 dicrotic, but the radial pulse becomes small- 

 er and less ample. The phenomena of con- 

 gestion observed in the brain persist for a 

 certain time after cerebral activity. 



