174 



NATURE 



\yune 23, 1 88 1 



Fig. 24.— Convulsions (New York). 



Fig. 27. — Typhoid Fevar. 



ning of December, when fogs become 

 II I iq most frequent, the curves for asthma 

 and bronchitis shoot up with startling 

 suddenness. 



Figs. 16, 17, and 18 represent the 

 curves for three of the nervous diseases, 

 viz. apoplexy, convulsions, and cephal- 

 itis. Apoplexy will be observed to show 

 a double-ridged maximum quite analo- 

 gous to that of the diseases of the re- 

 spiratory organs ; whereas, in the case 

 of convulsions, the maximum may be 

 regarded as quite single, and occurring 

 in spring, this being the season when 

 nervous diseases generally are most fatal. 

 On the other hand, the curve for cepha- 

 litis stands alone among nervous diseases 

 as having its annual maximum somewhat 

 later, and keeping above the mean till at 

 least the end of July, thus covering that 

 portion of the year when the climate is 

 - driest and hottest, as vi'ell as driest and 

 coldest. The intimate relations observed 

 between the curve for suicides (Fig. 19) 

 and that for cephalitis is very striking. 



The maximum mortality for whooping- 

 cough, Fig. 20, gout, Fig. 21, and 

 phthisis. Fig. 22, occur in the same 

 season as that for the nervous diseases. 

 The maximum mortality from whooping- 

 cough occurs in the spring months, and 

 the curve suggests that this is more a 

 disease of the nervous system than of 

 the respiratory organs, a view which, 

 singularly enough, was maintained by 

 the elder Dr. Begbie, one of the most 

 distinguished of our Edinburgh phy- 

 sicians, upwards of thirty years ago. 

 The relations of gout to diseases of the 

 '- nervous system are too obvious to call 

 for remark. Phthisis is one of the two 

 most fatal scourges of our British climate, 

 one out of every eight deaths which occur 

 being caused by consumption. Its mor- 

 tality-curve. Fig. 22, shows unmistakably 

 Q its intimate relations to nervous diseases, 

 thus affixing greater significance to its 

 known complications with hereditary 

 insanity, scrofula, and some other 

 mental diseases. 



Reference has been made to the influ- 

 ence of the heat of summer on certain 

 of the nervous diseases. That influence 

 acts fatally, both indirectly through the 

 bowels in the case of the young, and 

 directly on the nervous centres. The 

 curve for convulsions, Fig. 17, is identical 

 with that for teething, Fig. 23, and it 

 '_ may be added that the curve for hydro- 

 I I I d cephalus is simply a reproduction of the 

 same curves. Now these curves show 

 a small, but distinct, and, as revealed by 

 'l| each year's figures, a constantly recurring 

 secondary maximum in summer, which 

 in the case of London is almost wholly 

 due to the bowel complications of these 

 diseases. The curve (Fig. 24) for con- 

 vulsions for New York, where the sum- 

 mer temperature is iq-'o hotter than in 

 London, shows this feature of the curve 

 enormously magnified, so much so, in- 

 deed, that instead of being, as in London, 

 an insignificant secondary maximum, it 

 stands out as the prominent feature of 



