THE PREVENTION OF INFECTIOUS DISEASE. 429 



slight we may build our houses of wood and 

 thatch them with straw. Where, however, the 

 danger is greater we must build our houses 

 fireproof in order that when one house takes 

 fire a whole district shall not burst into flames. 

 Compared with the quality of material the 

 measure of extinguishing the separate sparks 

 is of less importance in preventing the spread 

 of the conflagration. The method of spark 

 chasing does not help much in the case of 

 buildings of wood and straw, as can be seen in 

 out-of-the-way villages, or even in Scandinavian 

 cities which are still built wholly of wood. 

 The satisfaction of afterwards seeing the in- 

 cendiary caught and punished helps no one to 

 regain his property. The extinction of sparks 

 will always be less valuable service to the civ- 

 ilized community than the intelligent construc- 

 tion of the house and the adaptation of it to 

 existing conditions. 



The combating of infectious diseases by war- 

 ring directly with the disease germs, the so- 

 called method of disinfection, must be kept 

 within reasonable limits and employed only 

 where we are able to assume that disease germs 

 really exist. 



It may facilitate our understanding of this 

 simple demand, which I advanced in 1889 * n 

 opposition to the standpoint of Koch, at that 



