Touching us as human beings even still more closely than the foregoing was the influence which chemistry had exerted on the science of pathology, and in no direction had greater progress been made than in the study of micro-organisms in relation to health and disease. In the complicated chemical changes to which we gave the names of fermentation and putrefaction, Pasteur had established the fundamental principle that these processes were inseparately connected with the life of certain low forms of organisms. Thus was founded the science of bacteriology, which in Lister's hands had yielded such splendid results in the treatment of surgical cases, and in those of Klebs, Koch, and others, had been the means of detecting the cause of many diseases both in man and animals, the latest and not the least important of which was the remarkable series of successful researches by Pasteur into the nature and mode of cure of that most dreadful of maladies, hydrophobia. The value of his discovery was greater than could be estimated by its present utility, for it showed that it might be possible to avert other diseases besides hydrophobia by the adoption of a somewhat similar method of investigation and of treatment.
Here it might seem as if we had outstepped the boundaries of chemistry, and had to do with phenomena purely vital. But recent research indicated that this was not the case, and pointed to the conclusion that the microscopist must again give way to the chemist, and that it was by chemical rather than biological investigation that the causes of diseases would be discovered, and the power of removing them obtained. For we learned that the symptoms of infective diseases were no more due to the microbes which constituted the infection than alcoholic intoxication was produced by the yeast cell, but that these symptoms were due to the presence of definite chemical compounds, the result of the life of these microscopic organisms. So it was 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 were to be traced, for it had been shown that the disease could be communicated by such poisons in the entire absence of living organisms.
Had time permitted, he would have wished to have illustrated the dependence of industrial success upon original investigation, and to have pointed out the prodigious strides which chemical industry in this country had made during the fifty years of her Majesty's reign. As it was, he must be content to remark how much our modern life, both in its artistic and useful aspects, owed to chemistry, and therefore how essential a knowledge of the principles of the science was to all who had the industrial progress of the country at heart. The country was now beginning to see that if she was to maintain her commercial and industrial supremacy, the education of her people from top to bottom must be carried out on new lines. The question how this could be most safely and surely accomplished was one of transcendent national importance, and the statesman who solved this educational problem would earn the gratitude of generations yet to come.
In welcoming the unprecedentedly large number of foreign men of science who had on this occasion honored the British Association by their presence, he hoped that that meeting might be the commencement of an international scientific organization, the only means nowadays existing of establishing that fraternity among nations from which politics appeared to remove them further and further, by absorbing human powers and human work, and directing them to purposes of destruction. It would indeed be well if Great Britain, which had hitherto taken the lead in so many things that are great and good, should now direct her attention to the furthering of international organizations of a scientific nature. A more appropriate occasion than the present meeting could perhaps hardly be found for the inauguration of such a movement. But whether this hope were realized or not, they all united in that one great object, the search after truth for its own sake, and they all, therefore, might join in re-echoing the words of Lessing: "The worth of man lies not in the truth which he possesses, or believes that he possesses, but in the honest endeavor which he puts forth to secure that truth; for not by the possession of truth, but by the search after it, are the faculties of man enlarged, and in this alone consists his ever-growing perfection.
Possession fosters content, indolence, and pride. If God should hold in his right hand all truth, and in his left hand the ever-active desire to seek truth, though with the condition of perpetual error, I would humbly ask for the contents of the left hand, saying, 'Father, give me this; pure truth is only for thee.'"
At the close of his address a vote of thanks was passed to the president, on the motion of the Mayor of Manchester, seconded by Professor Asa Gray, of Harvard College. The president mentioned that the number of members is already larger than at any previous annual meeting, namely, 3,568, including eighty foreigners.