54 DR- Bottomley on the late 



was communicated to him in the hope that it might be of 

 service in his future work on ozone ; on dipping the papers 

 into dilute hydrochloric acid, those which had been ozonised 

 and bleached re-assumed a violet tint ; those which had not 

 been exposed were initially unaffected. — "On the connec- 

 tion of the Humidity of the Air and the amount of Ozone." 

 Session i8y6-yy. — "On the Protection of Buildings from 

 Lightning " ; remarks on Professor Maxwell's paper on the 

 subject, read at the recent meeting of the British Association. 

 — "On Changes in the Rates of Mortality from Different 

 Diseases during the Twenty Years 1854-73," — a discussion 

 of the Registrar General's mortality returns during the 

 period, which he divides into two equal parts, comparing 

 the death rates of eight of the principal infectious diseases ; 

 the results show that the mortality from seven has diminished 

 very sensibly, while that from small-pox shows an extra- 

 ordinary increase, the percentage of increase of death rate 

 being 86-3 ; he also found that the adult portion of the 

 population were much more susceptible to its attacks. A 

 comparison of diseases of the non-preventible class during 

 the two periods showed for some an increase, and for others 

 a decrease. He also gives an analysis of the death returns 

 of a few of the more important diseases in the lists. From 

 his results he concludes that sanitary measures, tested by 

 their effect on the diseases which are universally admitted 

 to be infectious, have produced a slight improvement in the 

 public health which is equivalent to the saving of one life 

 in every 134, or a reduction of 0'I7 in the general death 

 rate ; but tested by their effect on the whole class of 

 zymotic diseases they have caused no improvement what- 

 ever, and have not even prevented an increase in the 

 mortality from these diseases, which is equivalent to an 

 extra loss of life in every 417. From the returns with 

 regard to small-pox, he states that the experience of the 

 last and of the present epidemic has furnished abundant 



