284 



NA TURE 



fJuLv 23, 1891 



I 



from diseases of the respiratory system by the lighter curve, and 

 the average number of deaths from disorders of the latter class by 

 a dotted line. The average mortality from influenza is too 

 small to permit of any curve being drawn upon the scale shown 

 in the diagram. 



Taking into consideration, firstly, the mortality from in- 

 fluenza alone, we find that not only was the duration of last 

 year's epidemic far less than that of the present year, but that 

 the number of deaths in the earlier period was very much smaller 

 than in the latter. The epidemic of 1890 set in with great 

 severity and suddenness at the beginning of January. During 

 the week ending December 28, 1889, there were no deaths in 



the epidemic prevailed with more or less severity, it appears 

 that the total number of deaths in London was 442, giving an 

 average of 74 per week. 



The visitation of the present year may be said to have com- 

 menced at the beginning of May. During the whole of April 

 there were a few deaths from influenza, the numbers in the four 

 weeks embraced by the Registrar-General's returns being re- 

 spectively 7, 3, 9, and 10. By the week ending May 2, how- 

 ever, the number had risen to 37, and from this time onward 

 the disease continued to spread with alarming rapidity, the 

 numbers in the three successive weeks being 148, 266, and a 

 maximum during the week ending May 23 of 319. In the two 



PIDEMIC OF 1890 



Epidemic of 189 



Week Ending 



Week Lnding 



Jan Jan Jan Feb Feb Feb May May|may May May Jun Jun Jun Jun Ji 



II 18 25 I 8 15 r ~ ' •' " ' 



London rom this disease, and in the following week only 4. 

 In the week ending January 11, 1890, however, the number 

 had risen to 67, while in the course of the ensuing seven days a 

 maximum of 127 was reached. The mortality then declined 

 steadily, the numbers in the four succeeding weeks being re- 

 spectively, 105, 75, 38, and 30. As a serious epidemic the 

 visitation may then be regarded as having spent itself, and in 

 preparing the dias^ram I have not considered it advisable to 

 include any period in which the weekly number of deaths fell 

 below 25. It may, however, be remarked that, for three weeks 

 subsequent to that shown by the curve, the mortality exceeded 

 20, while in the four succeeding weeks it ranged between 10 

 and 17. Taking as a whole the period of six weeks in which 



NO. I I 34, VOL. 44] 



ollowing weeks the mortality again exceeded 300, after which it 

 declined steadily to 249, 182, 117, and 56, while in the last 

 period shown by the diagram the number had fallen to 40. 

 Taking the period as a whole, it appears that during the eleven 

 weeks ending July 1 1 the total number of deaths in London 

 from influenza, irrespective of cases in which it was known 

 to have been present in the course of other diseases, was 2027, 

 giving an average of 184 per week, or about two and a half 

 times as much as the average mortality in 1890. In no fewer 

 than seven weeks out of the eleven the number of deaths 

 exceeded the maximum attained during the epidemic of last 



From an examination of the statistics given . in a valuable 



year, 



