414 



THE POPULAR SCIENCE MONTHLY 



occasion. Among the lecturers -who 

 will be present are Professor Emil 

 Borel, of Paris; Professor Hugo de 

 Vries, of Amsterdam; Professor Wil- 

 hehn Ostwald, lately of Leipzig; Sir 

 William Eamsay, of London, and Pro- 

 fessor Yito Yolterra, 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 Con- 

 gress of Eugenics, to which reference 

 has already been made m this journal; 

 the International Congress of Entomol- 

 ogy at Oxford, and the. International 

 Congress of Mathematicians at Cam- 

 bridge. The meeting of the British 

 Association for the Advancement of 

 Science at Dundee has also assumed in- 

 ternational proportions, in view of the 

 large number of foreign men of sci- 

 ence in attendance. 



TEE ADDEESS OF TEE PEE SI- 

 DENT OF TEE BEITISE 

 ASSOCIATION 



The presidential address before the 

 British Association for the Advance- 

 ment of Science given by Professor E. 

 A. Sehafer, of the University of Edin- 

 burgh, at Dundee, on September 4 has 

 attracted much attention in view of the 

 popular interest in questions concerned 

 with the nature, origin and mainte- 

 nance 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 fnmi 

 that of inorganic substances. But the 

 line between inorganic and organic 

 chemistry, which up to the middle of j 

 the last century appeared sharp, subse 



quently became misty and has now dis- 

 appeared. Similarly the chemistry of 

 living organisms, which is now a recog- 

 nized branch of organic chemistry, but 

 used to be considered as so much out- 

 side 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 moie 

 out of the hands of the biologist and 

 into those of the pure chemist. 



' ' Somewhat more than half a cen- 

 tury 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 compre- 

 hension of the properties of living sub- 

 stance. For it is becoming every day 

 more apparent that the chemistry and 

 physics of the living organism are es- 

 sentially 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 at- 

 tached to the molecules of the colloids. 

 Surrounding and enclosing the living 

 substance thus constituted of both col- 

 loid 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 mem- 

 brane, permitting of exchanges by dif- 

 fusion between the colloidal solution 

 constituting the protoplasm and the 

 circumambient medium in which it 

 lives. Other similar films or mem- 

 branes occur in the interior of proto- 

 plasm. 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 



