334 PLEASANT WA YS IN SCIENCE. 



the form of adipose tissue. The deposition of fat in such a 

 case will be far less injurious to the system than an excessive 

 heat-supply would be. But when only a just amount of 

 heat-giving food is taken, and in place of fulfilling its just 

 office this food is converted into adipose tissue, it becomes 

 necessary to inquire into the cause of the mischief. 

 Technically, the evil may be described as resulting from the 

 deficient oxygenation of the heat-supplying food. This 

 generally arises from defective circulation, and may often be 

 cured by a very moderate but systematic increase in the 

 amount of daily exercise, or by the use of the sponge-bath, 

 or, lastly, by such changes in the dress and especially in 

 the articles of attire worn next to the skin as tend to 

 encourage a freer circulation of the blood. The tendency 

 to accumulate fat may sometimes be traced to the use of 

 over-warm coverings at night, and especially to the use of 

 woollen night-clothes. By attending to considerations of 

 this sort, more readily and safely than by an undue diminu- 

 tion of the amount of heat-supplying food, the tendency to 

 obesity may frequently be corrected. 



In warm weather we should diminish the supply of heat- 

 giving food. In such weather the system does not require 

 the same daily addition to its animal heat, and the excess is 

 converted into fat Experiments have shown that despite the 

 increased rate at which perspiration proceeds during the 

 summer months, men uniformly fed throughout the year in- 

 crease in weight in summer and lose weight in winter. 



So far as mere existence is concerned, heat-forming food 

 may be looked upon as the real fuel on which the lamp of 

 life is sustained. But man, considerd as a working being, 

 cannot exist without energy-forming food. All work, whether 

 of the brain or of the limbs, involves the exhaustion of 

 nervous and muscular matter; and unless the exhausted 

 matter be renewed, the work must come to an end. The 

 supply of heat-giving food may be compared to the supply 

 of fuel for the fire of a steam-engine. By means of this 

 supply \htfirc is kept alive; but if the fire have nothing to 



