4S 



Proceedings of the Royal Irish Academy, 



In the tables and curTc-diagrams accompanying this paper, I have 

 shown the weekly variations of temperature and rainfall, and the 

 corresponding number of cases of the infectious diseases mentioned, 

 notified for each week, from 1900 to 1905, inclusive.^ 



The results of our inquiry, after a careful examination of the 

 tables and curve- diagrams, are to show — 



I. As regards Scarlatina. 



That there is a rise in the number of cases after there has been 

 deficient rainfall, and the number again falls after rain. Also, that 

 after a series of dry years, the number of cases increases. This bears 

 out Dr. Cresswell's observation, and also that of Dr. Longstaff, " That 

 the death-rate from scarlatina increases in years of deficient rainfall " ; 

 as it will naturally follow that, with a large increase in the number of 

 cases occurring, the number of deaths will be likely to rise also. 

 Temperature has apparently little or no influence. 



II. Measles. 



In the case of measles, neither rainfall nor temperature has 

 apparently any influence or anything to do with its spread. 



III. Typhoid Fever. 



Contrary to the well-known views of Yon Pettenkofer, the fore- 

 going table shows the number of cases occurring in any one year to 

 be quite independent of the fact as to whether it is a dry or a wet 

 year ; but the iveekly tables and diagram-curves show that there seems 

 to be a tendency for the number of cases to fall after rain, and to rise 

 in the dry weather. 



The number of typhoid cases dealt with in these tables is, however, 

 too small to generalize on. 



It is evident, therefore, that atmospheric temperatures have no 

 effect on the spread of these diseases. 



I have stated above that scarlatina and diphtheria show a marked 

 resemblance to each other in their method of spreading. Both increase 



' The tables and graphic diagrams referred to in this paper are preserved in 

 the Library of the Eoyal Irish Academy, and will be continued and printed in the 

 annual report on the Sanitary Condition of the County Borough of Birkenhead for 

 the year 1906. 



