The Chemist as Creator 755 



chemists are apt to do, and, again as chemists are apt to do, 

 he dissolved some gun-cotton [cellulose treated with nitric 

 acid in the presence of sulphuric] in ether-alcohol and 

 swabbed it on the wound. At this point, however, his con- 

 duct diverges from the ordinary, for instead of standing idle 

 impatiently waving his hand in the air to dry the film as 

 most people, including chemists, are apt to do, he put his 

 mind on it, and it occurred to him that this sticky stuff, 

 slowly hardening to an elastic mass, might be just the thing 

 he was hunting as an absorbent and solidifier of nitroglycer- 

 ine [the liquid result of mixing glycerine with nitric and 

 sulphuric acids]. So, instead of throwing away the extra 

 collodion he had made, he mixed it with nitroglycerine, and 

 found that it set to a jelly, 



the first of the high explosives of modern warfare. Every- 

 one knows that this collodion is much used as "new skin," which 

 has saved many lives, and in the cameras and cinemas that have 

 made so many people happy. And one might go on to show 

 how the cellulose of the saw-dust heap can be used to make the 

 soles of boots, the cushions of the car, the celluloid of the toilet- 

 table, and much more besides. 



3 



Capturing Nitrogen 



All living matter consists in part of proteins nitrogenous 

 carbon compounds, such as white-of-egg, casein, gluten. It fol- 

 lows that a normal diet to keep this living matter agoing must 

 include a supply of nitrogen. Animals cannot utilise nitrogen 

 except in the complex form of proteins which have been worked- 

 up by other animals or by plants. Plants get their nitrogen 

 supplies from nitrates, like saltpetre, and similar nitrogenous 

 salts in the soil. Therefore it becomes of fundamental importance 

 that the supply of nitrogenous salts in the soil should be kept up. 

 To some extent this comes about very naturally when the withered 

 residue of plants is, with the help of earthworms, incorporated 



