BIGGEST AND BUSIEST FACTORY 197 



motor cycle of this kind would require the alimentary 

 outfit of a human machine — a mouth with jaws to crush 

 the shale, a stomach or tank to hold a reserve store 

 sufficient to serve for a single journey, and a bowel or 

 feed-pipe which is capable of manufacturing a combustible 

 oil from the raw materials in the shale. The stomach or 

 store tank must be fitted with a sphincter mechanism to 

 regulate the discharge of its raw contents into the feed- 

 pipe, just as is the case in the human machine. Within 

 the feed-pipe must be fitted up all the chemical apparatus 

 needed for the conversion of the raw products in the 

 shale into a diffusible combustible oil. The interior of 

 the pipe must be so made that it will'immediately imbibe 

 or absorb the oil as it is formed and pass it on to the 

 circulation of the engine. A vent for the refuse or 

 excrement would have to be fitted to the feed-pipe, just 

 as is the case in the human machine. It is only when 

 one works out such a comparison that a full realisation 

 is obtained of the wonders which Nature has masked in 

 the intestine by giving it all the outward appearance of 

 extreme simplicity. Few people think of a sausage skin 

 as the husk of a living laboratory in which chemical 

 miracles went on all day long. 



Before we begin an examination of the construction 

 of the intestinal factory, we shall save time and make 

 our task easier if we first glance at the nature of the 

 work which has to be carried out in it. The chyme, as 

 it enters the duodenum from the stomach, has already 

 assumed the consistency of a fluid. The raw food 

 materials thus brought into the intestinal factory for 

 treatment fall into three main groups. The first and 

 chief group is made up of starches and sugars. They 

 have to be reduced to a kind of sugar which can be 

 absorbed and used within the body. These substances 

 are prepared or reduced by having molecules of water 

 forced into their composition. The wedge which Nature 

 uses for driving water molecules into starch is named 

 amylopsin — a ferment or enzyme, of which a very minute 

 quantity is effective. One of the businesses carried on 



