FROM DUST TO DUST. 57 



Prof. Halliburton, in his recent work, The Essefttiah of Chem- 

 ical Physiology, says — "The gastric juice is antiseptic ; the ])an- 

 creatic juice is not. . . . It is often difficult to say where 

 pancreatic action ends and bacterial action begins, as many of the 

 bacteria that grow in the intestinal contents, having reached that 

 situation in spite of the gastric juice, act in the same way as the 

 juice itself. Some form sugar from starch, others peptone, leucine, 

 and tyrosine, from other proteids ; while others, again, break up 

 fats. There are, however, certain actions that are entirely due to 

 these putrefactive organisms." It is a pity that the word "putre- 

 factive" is employed here, as it implies more than is really meant. 

 I need not enter into the details of the action of these intestinal 

 Anabiotic bacteria upon carbo-hydrates, proteids, and fats ; they 

 are carefully described in his book. Dr. Halliburton also tells us 

 how we are protected from an alkaloidal poison, called Choline, 

 by the bacteria which break it up into carbonic acid, methane, 

 and ammonia. 



Dr. Alexander Houston,* in his report upon the Scott-Moncreiff 

 sewage system, states " that bacteria exist in sewage, which are 

 capable of peptonising solid organic matter, or, in other words, of 

 preparing it by a process comparable to that of digestion for its 

 final destination. 



Thus far we have dealt with bacteria, which, as factors of 

 change, are friends rather than foes, and we have now attained 

 to the summit of life's wheel — where "perfect correspondence" 

 takes place by the " continual adjustment of internal relations to 

 external relations " — perfect metabolism — perfect life. 



The processes of evolution have been synthetic, constructive, 

 ever and ever becoming more complex as we ascend. The links 

 which form the chain of life are made up of one or more species, 

 whose component members are continually filling the gaps left by 

 their predecessors fallen by the way. What appear to be the weak 

 links are made up of the greatest ; while those which are stronger 

 are made up of the smallest numbers. No single link must long 

 remain too weak or too strong, or the perfect work of the whole 

 chain will be impaired. If a link should become too strong in 



* Nature, Report on Scott-Moncreiff Sewage System, by Dr. A. 

 Houston, 1894. 



