Januaey 13, 1905.] 



SCIENCE. 



57 



the application of mathematics to chem- 

 istry and some day they will be developed. 



So far we have considered problems in- 

 volving equilibrium only. When we begin 

 to study the conditions which make a reac- 

 tion possible and which govern its rate, we 

 are brought face to face with our need for 

 a satisfactory theory of catalytic agents. 

 We know experimentally the catalytic ac- 

 tion of many substances on many reactions, 

 but we have not even the first suggestion 

 of an adequate theory. This is a subject 

 of more vital importance than may appear 

 at first sight. I wish to call your attention 

 to two very important matters which de- 

 pend directly upon catalytic agents. The 

 first is the chemistry of plants. We can 

 make in the laboratory many of the sub- 

 stances which the plant makes. Some of 

 them, such as alizarine and indigo, we can 

 make more cheaply than the plant can, and 

 of a higher degree of purity. As yet we 

 can not make any of them in the way the 

 plant does, and this gap in our knowledge 

 will have to be filled by the physical chem- 

 ist, as the problem apparently does not 

 appeal to the organic chemist. The plant 

 does not use reverse coolers or sealed tubes ; 

 it does not boil with sulphuric acid or fuse 

 with caustic potash ; it has not metallic 

 sodium and chlorine gas as reagents. The 

 reagents on which the plant can draw are 

 air, water and a few mineral salts. As 

 catalytic agents it has heat, light, difference 

 of electrical potential, enzymes — and itself, 

 namely, living protoplasm. From the work 

 of Bredig and others we know that colloidal 

 metals, the so-ealled inorganic ferments, 

 can be substituted for enzymes in some 

 cases. As we do not yet know our limita- 

 tions, it is quite possible that we can substi- 

 tute inorganic catalytic agents for the en- 

 zymes in all cases. If that proves to be 

 true we can then duplicate everything ex- 

 cept the plant itself, and we shall be ready 

 to determine how closely we can duplicate 



the reactions of the plant. The experi- 

 ments of Sabatier and Senderens in France 

 are distinctly encouraging, even though 

 they do not carry us very far. By means 

 of nickel powder it is possible to reduce 

 acetaldehyde to alcohol with hydrogen at 

 30°. This is the best result that has been 

 obtained and it indicates the possibilities. 

 When we get a satisfactory theory of cata- 

 lytic agents we shall undoubtedly be able 

 to duplicate many of the plant syntheses 

 and our failures will be interesting as 

 bringing us nearer to the most difficult 

 problem of all — that of life. Pending the 

 development of a satisfactory theory of 

 catalytic agents, there is much to be done 

 in the way of experimenting. In view of 

 the fact that mixtures of two catalytic 

 agents often act more intensely than would 

 be expected from the behavior of each 

 taken singly, it would appear advisable to 

 determine the combined effects of inorganic 

 ferments and ultra-violet light. 



The second problem, which would be 

 easier of attack if Ave had a satisfactory 

 theory of catalytic agents, is that of the 

 transmutation of the elements. This is 

 now admitted to be distinctly a scientific 

 problem, though not one in which we have 

 made much progress. It is usually as- 

 sumed that it is a very difficult problem. 

 AVhile this may be true, we have not yet 

 reached the point where we are justified in 

 being certain of it. No one has ever at- 

 tacked the problem systematically and all 

 we can say is that the rate of change has 

 been small under any conditions that we 

 have yet realized. That is not surprising. 

 We should naturally expect a low reaction 

 velocity. The rate of change of radium is 

 so slight that it could not be detected by 

 any ordinary methods. The fact that we 

 have never observed any transmutation of 

 the elements does not prove that none has 

 taken place. We had been making dia- 

 monds artificially for years, even for cen- 



