742 TRANSACTIONS OF SECTION 1. 



concentration of the product of excretion, these solutes being more soluble in the 

 excreted medium than in the blood plasma, and distributing or diffusing them- 

 selves accordingly. If such a principle is applicable here as an explanation, it 

 may be quite as much so in other physiological cases in which the results are 

 supposedly due only to the forces postulated in the theories of van't Hoff and 

 Arrhenius. Whether this be so or not, the central fact remains that the enthusi- 

 astic hopes with which the theories were applied by physiologists and biologists 

 in the explanation of certain vital phenomena have not been wholly realised. 



The result has been a reaction amongst physiologists and biologists which 

 has not been the least contributory of all the causes that have led to the present 

 revival of vitalism. 



Another difficulty in accounting for the vital phenomena has been due, until 

 recently, to a lack of knowledge of the physical and chemical properties of 

 colloids and colloidal 'solutions.' The importance of this knowledge consistsin 

 the fact that protoplasm, ' the physical basis ' of life, consists mainly of colloids 

 and water. Till eleven years ago what was known regarding colloids was 

 derived chiefly from the researches of Graham (1851-62), Ljubavin (1889), Barus 

 and Schneider (1891), and Linder and Picton (1892-97), who were the pioneers in 

 this line. In 1899 were published the observations of Hardy, through whose 

 investigations very great progress in our knowledge of colloids was made. In 1903 

 came the invention of the ultramieroscope by Siedentopf and Zsigmondy, by which 

 the suspension character of colloid material in its so-called 'solutions' was visually 

 demonstrated. During the last seven years a host of workers have by their 

 investigations greatly extended our knowledge of the physical and chemical 

 properties of colloids, and now the science of Collochemistry bids fair, the more it 

 develops, to play a very important part in all studies bearing on the constituticn 

 and properties of living matter. 



Then, also, there are the phenomena of surface tension. This force, the 

 nature of which was first indicated by Segner in 1751, and described with more 

 detail by Young in 1804 and La Place in 1806 in the expositions of their theories 

 of capillarity, was first in 1869 only casually suggested as a factor in vital pro- 

 cesses by Engelmann. Since the latter date and until 1S92, when Butschli pub- 

 lished his observations on protoplasmic movement, no serious effort was made 

 to utilise the principle of this force in the explanation of vital phenomena. Even 

 to-day, when we know more of the laws of surface tension, it is only introduced 

 as an incidental factor in speculations regarding the origin of protoplasmic move- 

 ment and muscular contraction, and yet it is, as I shall maintain later on in 

 this address, the most powerful, the most important of all the forces concerned 

 in the life of animal and vegetable cells. 



It may be gathered from all that I have advanced here that the chief defect in 

 biological research has been, and is, the failure to apply thoroughly the laws of 

 the physical world in the explanation of vital phenomena. Because of this too 

 much emphasis is placed on the division that is made between the biological and tin 

 physical sciences. This division is very largely an artificial one, and it will in all 

 probability be maintained eventually only as a convenience in the classification t f 

 the sciences. The biologist and physiologist have to deal with problems in whi<h 

 a wide range of knowledge is necessary for their adequate treatment; and, if the 

 individual investigator has not a very extensive training in the physical sciences, 

 it is impossible for him to have at his command all the facts bearing on the subject 

 of his research, unless the problem involved be a very narrow one. The lack of 

 this wide knowledge of the physical sciences tends to specialism, and, as the 

 specialism is ever growing, it will produce a serious situation eventually, for it 

 will develop a condition in the scientific world in which co-ordination of effort and 

 a broad outlook will be much more difficult than is the case now. 



This growing defect in the biological sciences can only be lessened by the 

 insistence of those in charge of advanced courses in biological and physiological 

 laboratories that only they whose training is of a very wide character should be 

 allowed to take up research. It is, perhaps, futile to expect that such a rule will 

 ever be enforced, for in the keen competition between universities for young 

 teachers who have made some reputation for original investigation there may not be 

 too close a scrutiny of the qualifications of those who offer themselves for post- 

 graduate courses. There is ; further, the difficulty that the heads of scientific 



