Jlly 24, 1903.] 



SCIENCE. 



103 



well-controlled experiment was carried ont 

 at ililton, JIassachusetts, in 1809, with the 

 same result. 



The statistics of the early part of the 

 nineteenth century furnish the first evi- 

 dence of the eft'ect of vaccination as ap- 

 plied upon a large scale. In Sweden, for 

 example, the averag:e annual smallpox rate 

 per million was 1,914: from 1792 to 1801, 

 623 from 1802 to 1811, and 133 from 1812 

 to 1821. In Berlin the actual deaths from 

 the disease amounted to 4,453 for the ten 

 years 1782-91. 4,999 for the next decade, 

 2,955 for 1802-11, and 555 for 1812-22. 

 The facts are brought out in a still more 

 striking manner when the figures are plot- 

 ted graphically, as was done for London 

 from 1650 to 1900 by Dr. Newsholme.* 

 Wallace published a similar diagram of 

 the Swedish death rates which is alone 

 enough to convince a candid student that 

 something remarkably affected smallpox 

 mortality about 1800 ; but he closed his eyes 

 to its obvious teaching, and maintained 

 that inasmuch as the curve fell off sharply 

 from 1800 to 1803 before vaccination had 

 become general, the decrease was due not 

 to vaccination, but to 'sanitation.' It is 

 certainly true that the deaths from small- 

 pox decreased in the two or three years 

 after 1800 without reference to vaccination, 

 .iust as they had decreased periodically 

 after every epidemic in the eighteenth 

 century. But after every such previous 

 decrease the mortality had risen again 

 within five or ten years to another maxi- 

 mum. Why, after the decrease in 1803, 

 did the death rate in Sweden remain at 

 a minimum, never having risen since 1809 

 over 1.000 per million, and but four times 

 over 500, while in 1801 it was 2,566, in 

 1800 5.126, in 1799 1,609, in 1796 1,963 

 and in 1795 2,956? There is not the 



* ' The Epidoniiologj- of Smallpox in tlie Nine- 

 teenth Century,' British Medical Journal, July 

 .1, in02. 



smallest shred of evidence that 'sanitation' 

 received any great and sudden impetus 

 at exactly this time, unless sanitation be 

 used to cover all the arts which tend toward 

 'tlie prevention of premature death.' In 

 this wholly legitimate sense sanitation in- 

 cludes a number of prophylactic measures, 

 each adapted to the diminution of a specific 

 disease. When sanitation covered only 

 isolation and quarantine it could control 

 plague to a certain extent, but not small- 

 pox, not typhoid fever, not diphtheria, 

 not measles. When vaccination became a 

 sanitary measure, sanitation conquered 

 smallpox; but tjTihoid fever was not re- 

 stricted imtil the day of water supplies and 

 sewerage systems ; diphtheria, not until the 

 introduction of antitoxin. A fairly steady 

 decrease in the general death rate has, 

 indeed, occurred, due to a complex of fac- 

 tors not easily analyzed, but a sudden col- 

 lapse such as that which affected the 

 smallpox death rate after 1800 has never 

 been manifest without a definite and 

 tangible cause. That 'sanitation' has not 

 affected the other zymotics to the same de- 

 gree as smallpox has been graphically 

 shown by A. F. Burridge in a recent pub- 

 lication.* 



During the first quarter of the nineteenth 

 century it was thought that a .single vac- 

 cination ill infancy would give indefinite 

 l)roteetion against smallpox; but about 

 1830 this view began to lose ground. An 

 adult population now existed, protected, 

 not, as in other times, by previous attacks of 

 smallpox, but only by the less potent eft'ect 

 of vaccination. Smallpox began, therefore, 

 to recur, but modified in two notable re- 

 spects. In the first place, its age incidence 

 had shifted ; whereas of 1,252 cases in three 

 Prussian towns before vaccination began, 

 94.5 per cent, were under ten and not (me 

 over twenty years; of 1,677 cases in Wiir- 



" ' Vaccination and the Act of 1898,' Journal of 

 the Institute of Actuaries, October, 1902. 



