A THREATENED FACTORY 217 



he had to wring a livelihood from roots, husks, shell-fish, 

 and such game as he could capture. Then came man's 

 greatest discovery — the use and management of fire. 

 Food materials which previously had to be ground by 

 jaws and teeth and submitted to the operations carried on 

 in the great bowel before they yielded their quota of body 

 fuels, could now be prepared in a more easily assimilated 

 form by cooking. Then came another major discovery — 

 the provision of a steady and plentiful supply of food by 

 the culture of plants and the domestication of animals. 

 Cellulose, which was formerly digested by man himself, 

 was turned into beef and mutton by living factories which 

 were kept in byres and fields. Instead of struggling for 

 a livelihood from the chance products of the field, man 

 suddenly came to live in a world of plenty. Waste of 

 heat from the body was saved by the wearing of clothes 

 and the building of houses. The use of the quern and 

 of the mill saved the time and labour needed for mastica- 

 tion. Then in recent centuries man entered another 

 stage in his rapid progress, one in which the food products 

 of the world came to be emptied on the lap of civilisation. 

 He directed his efforts to obtain the most concentrated 

 and assimilable forms of food possible and succeeded. 

 Every means became employed for cooking and preparing 

 food to pamper and excite a jaded appetite, one often 

 beyond the natural needs of the body. The human 

 machine has thus come to be supplied with a form of fuel 

 for which its alimentary equipment was never designed. 

 Nature spent millions of years in fitting out a laboratory 

 to deal successfully with the natural refuse of the small 

 bowel ; and now under modern conditions of diet, we call 

 upon it to perform duties for which it was never intended. 

 When it breaks down from disuse or from having to deal 

 with refuse of a new kind, is it surprising that Nature levies 

 her fines ? What, then, is to be done — return to the life of 

 savages ? By no means ! A driver humours his engine 

 by supplying it with the kind and the amount of fuel it 

 is designed to burn. The human machine is designed 

 for a mixed diet of a kind which modern conditions of 



