ON CLASSIFICATION OF PERSONS EXPOSED TO SMALLPOX. 509 



cicatrices are of two kinds — either they are well-niarked, when 

 they cannot be distinguished from primary scars ; or they are 

 ill-marked, and can only be distinguished from those left by 

 the primary vaccination if the latter happen to be well marked. 

 In the coui'se of quarantine work many j)eople are now met with 

 who have knowledge enough to represenc themselves as re-vac- 

 cinated, and who believe that they get thereby a better chance of 

 early i-elease. As T have been brought to the conclusion that it is 

 for the most part impossible to tell from objective signs alone and 

 with certainty, whether a person is vaccinated or not, so I have 

 come to see that it must always be impossible so to tell whether 

 they have been re-vaccinated or not. This statement is not in- 

 tended, of course, to apply to re-vaccinations done within twelve 

 months or so ; scars of that age usually show sufficient evidence of 

 their recent formation. For these reasons I propose to head any 

 table classifying these, " persons who have been re-vaccinated," 

 but the reservation " as they allege " must be understood. They 

 should be subdivided into those who do and those who do not show 

 scars ; and here again the subject's statement alone is the ground 

 of distinction between those alleged to be respectively primary 

 and secondary. Lastly, each of these two groups must be further 

 subdivided by age ; as having been re-vaccinated, that is to say, 

 before or after the age of ten years (among Germans and some 

 Northern nations children re- vaccinated at all ages below ten are 

 met with). 



PROPOSITION IV. 



Unvaccinated persons ; persons who allege vaccination, but show 

 no scars ; persons who have been inoculated, and who do or do 

 not show unmistakable scars of a general eruption ; persons who 

 allege foregone smallpox, and who do or do not show unmistakeable 

 traces of it, and in whom it was primary or post- vaccinal ; these 

 must form classes apart, of which the members should be dis- 

 tinguished by age. 



Classification of Degrees op Illness. 



proposition v. 



All cases of smallpox should be classified as follows in respect 

 of severity of attack ; but cases of the primary disease and of 

 smallpox after vaccination, after inoculation, or after smallpox, 

 should be dealt with in separate tables. Attacks, during which 

 not more than fifty vesicles appear, should be called "very slight;" 

 those which show from that number up to two hundred or there- 

 abouts, should be called " slight" ; those cases usually discrimi- 

 nated as "discrete" (being those in which the number of vescicles 

 is such as conceivably might be counted) should be called 



