5 82 SCIENCE PROGRESS 



process of evolution — that, for example, giraffes, camels, hippo- 

 potami, and the monsters of the mesozoic swamps were not each 

 the result of a separate act of creation. There are now few to 

 doubt that our distant ancestors were extremely simple forms, 

 like the fungi or moulds, the algae that form the scum of ponds, 

 the bacteria whose invasions we have learned to dread. We 

 know that these and all other living forms are, chemically, a 

 fairly definable substance which we call protoplasm ; that the 

 chief constituent of this protoplasm is a complex compound 

 which we call protein ; and we are coming now to understand 

 pretty well the nature of protein. 1 



As recent work in the physiology of digestion 2 and in the 

 germination of plants, and the syntheses of Emil Fischer 3 have 

 shown, the proteins in turn are made up of compounds known 

 as amino acids ; these are, in Fischer's phrase, the basic sub- 

 stances or " Bausteine " of all living matter whatsoever. These 

 amino acids themselves represent varying compounds of a 

 carbohydrate, a simple sugar or kindred combination of carbon 

 and water, with the radicle of ammonia, NH 2 . Very recently 

 Ciamician 4 has shown that an amino acid may be derived from 

 the reaction of prussic acid on acetone, under the influence of 

 light. In turn, W. Lob has shown that formaldehyde may be 

 produced by the action of the silent electrical discharge on a 

 mixture of carbon dioxide and water. 5 



It is true that no one has as yet been able to produce life 

 from amino acids, any more, for example, than a few years ago 

 any one was able to devise a machine and fly through the air 

 like a bird. There was no very great mystery about aviation, 

 though the practical difficulties seemed insuperable. In the 

 same way, to those who have followed the splendid development 

 of bio-chemistry within the last five or ten years, and especially 

 within the last one or two years, there is no very great mystery 

 about the chemical nature of life. 6 



The distance passed over in the complication of a protozoan 

 to the marvellous mechanism which is man, or from a proto- 



1 Mann, Chan, of the Proteids, p. 8, 1908. 



2 Starling, Recent Advances, p. 8, 1906. 



3 Untersiichungcn, 1906. 



4 La Chi mica organica negli Organismi, p. 28, 1908. 



5 Zeit.f. elek. Chemie, 12, 282, 1906 ; Landw. Jahrb. 35, 54, 1906. 



6 Cf. Loeb, Dynamics of Living Matter, p. 7, 1906 ; O. Loew, Chem. Energie 

 d. leb. Zellen, p. 6, 1906. 



