PROBLEMS OF CHEMISTRY 309 



hydrogen, and oxygen, which are the only elementary sub- 

 stances found in the fats how one could make in the lab- 

 oratory the same fats that occur in living things. No one 

 has ever done this, but it appears highly probable that, with 

 unlimited time at one 's disposal, it could be clone by making 

 use of methods that are made use of every day in the lab- 

 oratory. Not many years ago that statement would have 

 been challenged. The constituents of plants and animals 

 were supposed to be entirely different from the constituents 

 of the inanimate inorganic parts of the earth, and it was 

 further supposed that those substances which are elaborated 

 under the influence of the life-process cannot be formed 

 without this influence. This may be true of the most com- 

 plex constituents of plants and animals, but it is certainly 

 not true of some of the simpler of these constituents. For 

 example, urea, one of the most characteristic substances 

 formed in the animal body, was made in the laboratory in 

 1828, by a method which was entirely independent of the 

 life-process; and since that time innumerable other sub- 

 stances which are characteristic products of the life-process 

 have been made artificially. So that, as we know very well 

 what fats are, and can make substances of the same kind 

 in the laboratory, there is nothing out of the way in saying 

 that the fats could probably be made artificially. Let us 

 assume that they can be. What then? 



Next in order of complexity come the so-called carbo- 

 hydrates, which include the sugars, starch, and cellulose. 

 Is it "highly probable" that the chemist can build these 

 up out of the elements in the laboratory? Thanks to 

 Emil Fischer, of Berlin, we can now almost say that sugar 

 is not an unsolved problem. Within the last few years 

 more has been done to clear up the problem of the sugars 

 than in all preceding time put together. One of the sim- 

 plest sugars has been prepared artificially in the laboratory, 

 and the relations between the others have been, to a large 

 extent, revealed. 



But the sugars are simple things compared with starch. 



