178 MESSRS. RANSOME AND VERNON ON THE INFLUENCE 



the fluctuations in the atmospheric pressure were far 

 greater than when it was less rife. 



Measles seem to be much influenced by the same con- 

 ditions as whooping cough, since it is usually most preva- 

 lent during the same seasons; and yet it is evident that 

 this relation is not exacts since in many of the lesser un- 

 dulations of the measles-curve the variations take place in 

 the opposite direction to those of whooping cough. (This 

 is the case in twenty-nine out of the seventy-five weeks 

 noticed^ about 38 per cent.) 



On comparing the curve from April 18^7 to March 1858 

 with the degree of humidity, it seemed that this element 

 had some effect upon the lesser undulations of the disease- 

 curve, since the number of cases rose and fell with the 

 humidity in 72 per cent of the weeks ; but on comparing 

 the second period, from April 18^8 to October 18^8, this 

 hypothesis is not borne out, and the coincidence may be 

 accidental, since in one half the weeks the variations went 

 with the degree of humidity, in the other half they went 

 in the opposite direction. Moreover, although in October, 

 while the degree of humidity is rapidly rising, the disease 

 prevails very greatly, yet in March 1858, when the num- 

 ber of cases reaches its maximum, the degree of humidity 

 is very low; and in September and October 1858, when 

 the relative amount of moisture in the air is the greatest, 

 the number of cases is at its minimum. 



' Whooping Cough 



Seems to be much influenced by the extremes of heat 

 and cold, the curve, on the whole, rising with the fall and 

 sinking with the rise of temperature. 



The disease remains apparently unaffected by the gra- 

 dually increasing warmth of the spring of 18^7, but a 

 decided diminution of the number of cases follows as soon 

 as the mean temperature of the week rises to 6'j°, which 

 takes place in the week ending June 27 th 18^7. 



