62 PROCEEDINGS OF THE COTTESWOLD CLUB 



and renewal of the combination of the body-substance — 

 two properties necessary to Hving creatures depend — viz. : 

 the secretion of food and the excretion of waste products. 

 Nevertheless this important property of hving creatures, 

 viz. : metabohc action, may under certain circumstances 

 be temporarily suspended or suppressed without thereby 

 depriving the creature, or organism, of the power of 

 existence. By removal of water or heat, it is possible, in 

 the case of many of the lower organisms and their germs, 

 to suspend the vital principle for months and even for years, 

 and then to restore the apparently lifeless body to the 

 full exercise of its vital properties by the simple addition 

 of water or warmth. Such is the case with the eggs of 

 Apus — one of the Entomostraca, of the Cypris, a cuirassed 

 ostracod, which is found in our ponds and ditches, and 

 other hke forms, and of frogs and other animals. The 

 intensity of respiration stands in direct relation to the 

 energy of the metabolism. Animals which breathe by 

 means of gills and absorb but little oxygen, arc not, of 

 course, in a position to oxidize a large quantity of organic 

 constituents, and can only transform a small quantity of 

 potential into active energy. They perform, therefore, 

 not only a proportionately smaller amount of muscular 

 and nervous work, but also j)roduce in only a small 

 degree the peculiar molecular movements known as heat. 

 The source of this heat is to be sought, not in the 

 respiratory organs, but in the active tissues. Animals, in 

 which thermogenic activities are small, have no power of 

 keeping independently their ow^n internal heat when exposed 

 to the influence of the temperature of the surrounding 

 medium. This is also true of those air-breathing animals 

 in which the metabolic and thermogenic activities are great, 

 but which in consequence of their small size offer a relatively 

 large surface for the loss.of heat by radiation, as in the case 

 with many insects and the lower orders of animals. On 

 account of the changes of heat which are constantly 



