ADDRESS. 25 



and putrefaction, the views of Liebig, according to which these pheno- 

 mena are of a purely chemical character, have given way under the 

 searching investigations of Pasteur, who established the fundamental 

 principle that these processes are inseparably connected with the life of 

 certain low forms of organisms. Thus was founded the science of bacte- 

 riology which in Lister's hands has yielded such splendid results in the 

 treatment of surgical cases ; and in those of Klebs, Koch, and others, 

 has been the means of detecting the cause of many diseases both in man 

 and animals; the latest and not the least important of which is the re- 

 markable series of successfal researches by Pasteur into the nature and 

 mode of cure of that most dreadful of maladies, hydrophobia. And here 

 I may be allowed to refer with satisfaction to the results of the labours on 

 this subject of a committee, the formation of which I had the honour of 

 moving for in the House of Commons. These results confirm in every 

 respect Pasteur's assertions, and prove beyond a doubt that the adoption 

 of his method has prevented the occurrence of hydrophobia in a large 

 proportion of persons bitten by rabid animals, who, if they had not been 

 subjected to this treatment would have died of that disease. The value 

 of his discovery is, however, greater than can be estimated by its present 

 utility, for it shows that it may be possible to avert other diseases besides 

 hydrophobia by the adoption of a somewhat similar method of investiga- 

 tion and of treatment. This, though the last, is certainly not the least 

 of the debts which humanity owes to the great French experimentalist. 

 Here it might seem as if we had outstepped the boundaries of chemistry, 

 and have to do with phenomena purely vital. But recent research indi- 

 cates that this is not the case, and points to the conclusion that the 

 microscopist must again give way to the chemist, and that it is by chemical 

 rather than by biological investigation that the causes of diseases will be 

 discovered, and the power of removing them obtained. For we learn 

 that the symptoms of infective diseases are no more due to the microbes 

 which constitute the infection than alcoholic intoxication is produced by 

 the yeast- cell, but that these symptoms are due to the presence of definite 

 chemical compounds, the result of the life of these microscopic organisms. 

 So it is to the action of these poisonous substances formed during the 

 life of the organism, rather than to that of the organism itself, that the 

 special characteristics of the disease are to be traced ; for it has been 

 shown that the disease can be communicated by such poisons in entire 

 absence of living organisms. 



If I have thus far dwelt on the progress made in certain branches of 

 pure science it is not because I undervalue the other methods by which 

 the advancement of science is accomplished, viz., that of the application 

 and of the diffusion of a knowledge of nature, but rather because the 

 British Association has always held, and wisely held, that original investi- 

 gation lies at the root of all application, so that to foster its growth and 

 encourage its development has for more than fifty years been our chief 

 aim and wish. 



