ATMOSPHERIC ELECTRICITY AND OZONE. 465 



toms of influenza and the symptoms of an over-dose of ozone. Ex- 

 periments on animals have shown that irritation of the mucous lining 

 of the throat and nostrils, with febrile symptoms and congestion of 

 the lungs, may be quickly excited by breathing air containing a large 

 percentage of ozone. If animals are, for a long time, subjected to 

 ozone, they perish. In their susceptibility to it, however, they vary 

 widely. A rabbit, breathing air mingled with -g-oYo of its weight in 

 ozone, has died in two hours. Mice, breathing air about -g-oVo °f 

 ozone, have died immediately. Rats are more susceptible than Guinea- 

 pigs, and Guinea-pigs are more susceptible than rabbits. Pigeons are 

 quite tolerant of ozone, and frogs are proof against it, provided they 

 have abundance of water. Birds are specially tolerant of this agent, 

 as might naturally be inferred, since, in the higher strata of the air, 

 where they fly, ozone is more abundant than near the earth. 



It has been stated that there is a relation between ozone and inter- 

 mittent and remittent fevers ; that rheumatism is prevalent when 

 ozone is deficient ; that, when ozone is in excess, diphtheria, quinsy, 

 small-pox, herpes, measles, scarlatina, and other cutaneous affections, 

 prevail; and that, during the visitation of the cattle-plague in Eng- 

 land, ozone was below the usual standard. 



There is considerable more of evidence to show that visitations of 

 cholera are accompanied with a diminution in the atmospheric ozone. 



Experiments have shown that germs, sporules, bacteria, vibriones, 

 and small monads, with other low forms of life, are destroyed by 

 ozone. On the accepted view that epidemic and infectious diseases 

 are caused by spores, bacteria, etc., we can understand how a de- 

 ficiency of ozone in the air may invite disease. 



The only conclusions on this subject of the relation of atmospheric 

 ozone to disease, that at present seem justifiable, are these : 



1. A deficiency of ozone in the air probably has a certain relation 

 to epidemic and chronic disease. 



2. Deficiency of ozone invites disease, by debilitating the system, 

 and thus making it less capable of contending with morbid influences. 



Tests for Ozone. — Of the various tests for ozone, those which are 

 most used are starch and iodide of potassium. Fox prefers the 

 iodized litmus and the simple iodide of potassium test. The litmus- 

 paper and the iodide of potassium must both be pure. The Swedish 

 filtering-paper is the best. Blue litmus is purified by boiling, etc., 

 until it is of a vinous red color. The strips of filter-paper are plunged 

 for one-third of their length into a solution of neutral iodide of potas- 

 sium, made by dissolving 15^ grains in 321 grains of distilled water. 



These tests are exposed to the air for twelve or twenty-four hours 

 beneath a plate. If ozone be present in the air, the iodized part be- 

 comes blue, and the non-iodized part is unchanged. Sometimes the 

 test-paper is placed in ozone-boxes, so constructed that a current of 

 air passes through them. 



VOL. IV. — 30 



