510 PROCEEDINGS OF SECTION H. 



" moderate " ; while the semi-confluent and confluent degrees 

 should be called " severe," and should be farther divided under 

 a sub-head, showing which of them were "fatal." 



Note on the Classification of the degrees of Illness. — In this respect 

 I propose a change with greater diffidence. But as we now say 

 that vaccination tends to avoid death rather than attack (implying, 

 as well, that it avoids the serious constitutional damage so common 

 after the primary disease), and as it is certainly known that vaccina- 

 tion does modify the disease with some limitation as to time, the 

 important question now seems to be — " How much did the 

 patient sufier ?" 



I now ask attention to a few tables which show this scheme of 

 classification brought to practical test ; they are copied from my 

 report to the President of the Board of Health, on the case of the 

 mail .steamer Preussen, which was presented to the Chief Secretary 

 at the beginning of the year 1887. But before they are examined 

 I think it advisable to repeat what is already said in the title of 

 this communication, namely, that it is a scheme for showing the 

 incidence of smallpox upon persons who have been exposed to 

 infection and their difiei^ent degrees of protection by vaccination 

 as at present practised. AVhatever it may be worth, its value, and 

 that of any similar scheme, is but secondary — but an expedient 

 by which an actually existing practice may in the end be rendered 

 a little less uncertain than at present in individual cases it is. 

 Consideration of Jenner's practice and of his results shows clearly 

 enough that quality of lymph is the thing ; and that if the large 

 proportion of post-vaccinal smallpox now witnessed be capable of 

 reduction, that i-eduction will be eflected by improving, not methods 

 of operation, but methods of lymph-cultivation. 



(Extracted from " A Report upon an outbreak of small-pox on board the ss. Preussen, 

 Anno. 1886.") 



Analysis of the state as to vaccination of, and the incidence of 

 small-pox upon 312 passengers landed at the Quarantine Station, 

 Port Jackson. 



Note. — In considering the following figures it must be always remembered 

 that the numbers dealt with are extremely small ; and that although state- 

 ments of percentages are made they have no significance of general applica- 

 tion. The influence of vaccination upon susceptibility to small-pox has been 

 deduced from many million observations, and the i-esults of this unparalleled 

 experience may be stated as laws. But their application is true only of 

 large numbers of persons. The fate of individuals or of small communities 

 cannot be foretold by them. 



