Page:Popular Science Monthly Volume 81.djvu/420

414 occasion. Among the lecturers-who will be present are Professor Emil Borel, of Paris; Professor Hugo de Vries, of Amsterdam; Professor Wilhem Ostwald, lately of Leipzig; Sir William Ramsay, of London, and Professor Vito Volterra, of Rome.

While a larger group of foreign scientific men are in this country than ever before, a considerable number of American scientific men have attended three international congresses held in England—the First International Congress of Eugenics, to which reference has already been made m this journal; the International Congress of Entomology at Oxford, and the. International Congress of Mathematicians at Cambridge. The meeting of the British Association for the Advancement of Science at Dundee has also assumed international proportions, in view of the large number of foreign men of science in attendance.

The presidential address before the British Association for the Advancement of Science given by Professor E. A. Schäfer, of the University of Edinburgh, at Dundee, on September 4 has attracted much attention in view of the popular interest in questions concerned with the nature, origin and maintenance of life. While the address does not contain new facts or theories, it is a clear and excellent statement of the chemico-mechanical explanation of life. The entire address was published in the issue of Science for September 6. We may quote several paragraphs, which are characteristic of the line of argument:

"It is not so long ago that the chemistry of organic matter was thought to be entirely different from that of inorganic substances. But the line between inorganic and organic chemistry, which up to the middle of the last century appeared sharp, subsequently became misty and has now disappeared. Similarly the chemistry of living organisms, which is now a recognized branch of organic chemistry, but used to be considered as so much outside the domain of the chemist that it could only be dealt with by those whose special business it was to study 'vital' processes, is passing every day more out of the hands of the biologist and into those of the pure chemist.

"Somewhat more than half a century ago Thomas Graham published his epoch-making observations relating to the properties of matter in the colloidal state: observations which are proving all-important in assisting our comprehension of the properties of living substance. For it is becoming every day more apparent that the chemistry and physics of the living organism are essentially the chemistry and physics of nitrogenous colloids. Living substance or protoplasm always, in fact, takes the form of a colloidal solution. In this solution the colloids are associated with crystalloids (electrolytes), which are either free in the solution or attached to the molecules of the colloids. Surrounding and enclosing the living substance thus constituted of both colloid and crystalloid material is a film, probably also formed of colloid, but which may have a lipoid substratum associated with it (Overton). This film serves the purpose of an osmotic membrane, permitting of exchanges by diffusion between the colloidal solution constituting the protoplasm and the circumambient medium in which it lives. Other similar films or membranes occur in the interior of protoplasm. These films have in many cases specific characters, both physical and chemical, thus favoring the diffusion of special kinds of material into and out of the protoplasm and from one part of the protoplasm to another. It is the changes produced under these physical conditions associated with those caused by active chemical agents formed within protoplasm and known