454 ANNUAL REPORT OF THE Off. Doc. 



iQeu, shoulder to shouldei- with the State and the whole population; 

 but now the nionieut when such co-operation is possible seems to 

 have come. I suppose there is hai-dly any medical man now who de- 

 nies the parasitic uatut-e of tuberculosis, and among the non-medi- 

 cal public too the knowledge of the nature of the disease has been 

 widely propagated. 



Another favorable circumstance is that success has recently been 

 achieved in the combaiing of several parasitic diseases, and that we 

 have learned from these examples how the conflict with pestilences 

 is to be carried on. 



The most important lesson we have learned from the said exper- 

 ience is that it is a great blunder to treat pestilences uniformly. 

 This was do«e in former times; no matter whether the pestilence in 

 question was cholera, plague, or leprosy; isolation, quarantine, use- 

 less disinfection were always resorted to. But now we know that 

 every disease must be treated according to its own special individ- 

 uality, and that the measures to be taken against it must be most ac- 

 curately adapted to its special nature, to its etiology. We are en- 

 titled to liope for success in combating tuberculosis only if we keep 

 this lesson constantly in view. As so extremely much depends just 

 on this point, I shall take the liberty to illustrate it by several ex- 

 amples. The pestilence which is at this moment in the foreground of 

 interest, the bubonic plague, may be instructive to us in several re- 

 spects. 



People used to act upon the conviction that a plague patient was 

 in the highest degree a centre of infection, and that the disease was 

 trausmitted only by plague patients and their belongings. Even the 

 most recent international agreements are based on this conviction. 

 Although, as compared with formerly, we now have the great ad- 

 vantage that we can, with the aid of the microscope and of experi- 

 ments on animals, recognize every case of plague with absolute cer- 

 taiot}-, and although the prescribed inspection of ships, quarantine, 

 the isolation of patients, the disinfection of infected dwellings and 

 ships, are carried out with the utmost care, the plague has, never- 

 theless, been transmitted everywhere and has. in not a fesv places, 

 assumed grave dimensions. Why this has hap[)eued we know very 

 well, owing to the experience quite recc^ntly gained as to the man- 

 ner in which the plague is transmitted. It has been discovered that 

 only those plague i)atients that sutler from plague-pneumonia — a 

 condition which is fortunately infrequent — are centres of infection, 

 and that the real transmitters of the plague are the rats. There is 

 no longer any doubt that, in by far the majority of the cases in which 

 the plague has been transmitted by ocean tralfic, the transmission 

 took place by means of plague among the ship rats. It has also been 



