826 THE POPULAR SCIENCE MONTHLY. 



verted into the living material of the animal itself before it does any 

 work, and therefore it must be the wear and tear of the machine itself 

 which supplies the working-power, and not that of the food as mere 

 fuel-material shoveled directly into the animal furnace. 



I therefore agree with Playfair, who says that the modern theory 

 involves a " false analogy of the animal body to a steam-engine," and 

 that " incessant transformation of the acting parts of the animal ma- 

 chine forms the condition for its action, while in the case of the steam- 

 engine it is the transformation of fuel external to the machine which 

 causes it to move." Pavy says that " Dr. Playfair, in these utterances, 

 must be regarded as writing behind the time." He may be behind as 

 regards the fashion, but I think he is in advance as regards the truth. 



My readers, therefore, need not be ashamed of clinging to the old- 

 fashioned belief that their own bodies are alive throughout, and per- 

 form all the operations of working, feeling, thinking, etc., by virtue of 

 their own inherent, self-contained vitality, and that in doing this they 

 consume their own substance, which has to be perpetually replaced by 

 new material, the quality of which depends upon the manner of working, 

 and the matter and manner of replacement. We may thus, according 

 to our own daily conduct, be building up a better body and a better 

 mind, or one that shall be worse than the fair promise of the original 

 germ. The course of our own evolution depends upon ourselves, and 

 primarily upon the knowledge of our own physical and moral consti- 

 tution, and their relations to the external world. Of such knowledge 

 even the humble element supplied by " The Chemistry of Cookery " 

 is one that can not be safely neglected. — Knowledge. 



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1NTER]S"AL AEEANGEMENT OF TOWN-HOUSES. 



By EGBERT W. EDIS, F. S. A. 



/^ GOD planning means not merely the arrangement of a certain 

 vIT^ number of rooms on a certain number of floors, but careful and 

 close attention to the general domestic requirements and arrangements 

 of the ordinary householder, and to all smaller details which make up 

 the comfort and convenience of the house. It means that every foot 

 of space shall be properly laid out, that there shall be no dark corners, 

 and no inaccessible places, and that every room, closet, and staircase 

 shall have ample light and ventilation, and that staircases shall be 

 conveniently arranged, easy, with broad landings, and of sufficient 

 width to allow of passing conveniently. 



Each room has to be considered, and its relative proportion and 

 position in the plan. The dining-room, or general eating-room of a 

 house, should be so arranged that, although above the kitchen-level, 



