at points of average accessibility; but, as the policy of the Association embraces the whole country in the sphere of its influence, and as it is designed, at least partially, to encourage the popular interest in science by visiting successively all the leading cities, it is well that outlying places should not be habitually neglected. The strangers were welcomed with the most hospitable entertainment by the citizens of Minneapolis, and everything was done to make their visit agreeable.
The work of the American Association on this occasion was excellent on the whole, and does not suffer by comparison with that of previous gatherings. There was a large list of papers of quite average merit, and some of them of unusual interest. Able addresses were delivered by the chairmen of the sections, and the one by Professor Rowland, of Johns Hopkins University, before the Section of Physics, we hope to give our readers in the next number of the "Monthly." The retiring president, Principal Dawson, of Montreal, gave an able address on "Some Unsolved Problems in Geology," the first part of which will be found in our columns this month. It is mainly devoted to a discussion of the evolution hypothesis, of which Dr. Dawson can not be claimed as an adherent, and he improved the occasion to give a forcible exposition of its difficulties from the geological point of view. It is undeniable that these difficulties are many and formidable, and it will, no doubt, take a long time to clear them up, while the solution of still unresolved problems will very possibly result in important modifications of the theory as now entertained. But the establishment of the doctrine of evolution as a comprehensive law of nature is no longer dependent upon its freedom from embarrassments or that absolute completeness of proof which will only become possible with the future extension of knowledge. Notwithstanding these drawbacks, the evidence for it is so varied, so consistent, and so irresistible, as to compel its broad acceptance by men of science, who, while disagreeing upon many of its questions, acknowledge that it is now indispensable as a guide to the most multifarious investigations. It is gratifying to observe that the spirit of passion, dogmatism, and prejudice, which has been so rife in connection with this discussion during the past generation, is measurably subsiding, and that the controverted questions that remain are considered with increasing calmness, candor, and loyalty to truth.
Some offense has been taken at parts of Dr. Shepherd's article on "Medical Quacks and Quackeries," which appeared in our June issue. The writer ranked homœopathy as a form of quackery, and cited certain of the dogmas of Hahnemann, founder of the school, in justification of his charge. "The Popular Science Monthly" is censured for lending the weight of its authority to this accusation, and we have received sundry replies to Dr. Shepherd's strictures, of various merit, one of which, from an eminent source, is herewith printed.
It seems hardly correct to charge the "Monthly" with lending its influence to partisan objects in this matter, because the expression of an opinion on the part of a contributor by no means commits the magazine to it. Many periodicals advertise that the editors do not hold themselves responsible for the views of their writers: we have not done this, because it seemed superfluous. We often print statements with which we do not agree, and sometimes express dissent; but it by no means follows that a failure to protest is to be construed into an indorsement of all that appears in our pages; while certainly no one would expect that we should limit ourselves to printing only