N. MATERIA MEDICA, THERAPEUTICS, AND HYGIENE. 563 



vised by Professor G. Bischof, of Glasgow, which consists 

 essentially in filtering the water through spongy iron and 

 pounded limestone. The iron is placed in the upper cham- 

 ber of an earthenware filter, and powdered limestone is ar- 

 ranged in a separate layer below. The iron is procured in a 

 powdery, spongy state by the reduction of an ore without 

 fusion, after the extraction of sulphur and copper by heat. 

 It removes all albuminoid and nitrogenized compounds, and 

 also all bad contaminations from the water; and a trace of 

 iron taken up by the water is separated by its subsequent 

 passage through the limestone. It is stated that one charge 

 of the material, costing one shilling, is sufficient for the filter- 

 ing often gallons per day for a period of two hundred days. 

 21 A, August 15, 1873, 755. 



THE PHYSIOLOGICAL ACTION OF OZONE. 



Owing to the important influence which, according to 

 some physicists, even the smallest trace of ozone in the at- 

 mosphere exercises upon the health of human beings, a spe- 

 cial interest attaches to the researches recently published, by 

 Mr. Dewar and Dr. M'Kendrick, on the physiological action 

 of ozone, when contained in much larger percentages than 

 ordinarily happens in nature. Upon breathing an atmos- 

 phere of ozonized air that is to say, air highly charged with 

 ozone the authors experienced the following effects: a suf- 

 focating feeling in the chest, a tendency to breathe slowly, 

 irritation of the fauces and glottis, a tingling of the skin of 

 the face, and a feebler pulse. The inhalation was continued 

 for eight minutes, when they were obliged to desist; and the 

 experiment was followed by a violent irritating cough and 

 sneezing, and for five or six hours thereafter by a sensation 

 of rawness in the throat and air-passages. Experiments 

 were made on warm and cold blooded animals, and on the 

 separate individual living tissues of the body. Among the 

 results we note the following, in addition to the phenomena 

 above mentioned, which appear to have been very generally 

 experienced. The blood is found after death to be in a ve- 

 nous condition, both in cases of death in an atmosphere of 

 ozonized air and in ozonized oxygen. The inhalation of an 

 ozonized atmosphere is followed by a lowering of the tem- 

 perature of the body to the extent of ten or twelve degrees. 



