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Sect. XIV.] MEDICINE AND MEDICAL STATISTICS. 



459 



will be the value of the mforrnation. 



as during a 



pro- 



tract" d exposure there 1^ not any means of even approxi- 

 mately ascertaining when the system had acquired the 

 reqrasite charge necessary to the evolutioij of the disease ; 

 although the latent period of endemic and epidemic dis- 

 eases is a subject ^yhich is both curious and interesting ; 

 still as regards contagious diseases it is infinitely more so* 

 as it is principally on a correct knowledge of these periods 



that the quarantine laws can be efficiently administered, 

 With a know^'^dge of these facts it vvll] not be saying 



too much to aiBrm. that it greatly behoves the medical 



officer of the naval service to lose no opportunities of 



record a succinct history of every case of 



lacin 



piacmg on 



disease, which has been contracted 



exposi 



specific exciting cause for so short a period as will serve 

 to mark the stage of incubation to a single day. There 

 may by this means be such a mass of evidence brought to 

 bear on the subject, as Mall greatly simplify our view^s on 

 the doctrines of contagion, and at the same time dis- 

 embarre^^ the 'laws of quarantine of many 



restrictive 



' formalities, that are not only useless in a sanitary point 

 of view, but injurious to commerce, and personally vexa- 



tious. 



As the preceding observations are applicable more or 



le^ in a general way to other endemic, epidemic, or con 



tagio-is disease 





it will be unnecessary to go over the 



sr* u^ ground with respect to them. The incubative 

 period of plague, and if it rage epidemically, proof of its 

 having, independently of epidemic influence, acquired 

 contagious properties which have been transmitted from 

 (ine person to another, either simply through the medium 



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