6 THE ROYAL SOCIETY OF CANADA 



the chemical constitution of this protoplasm. No matter, living or 

 dead, can exist outside the pale of chemical laws. That life is largely 

 a chemical affair hardly needs proof at tliis late date. In the process 

 of respiration we have the chemical union of oxygen with hsemoglobin, 

 and in the internal or tissue respiration the union of this same oxygen 

 with other elements, like carbon, hydrogen, sulphur, and phosphorus, 

 contained in the cells and tissue juices. Digestion is largely a matter 

 of chemistry, and, up to a certain point, ma}' proceed in vitro almost 

 as well as in the stomach and intestine. Absorption and assimilation 

 are in great measure chemical processes. In the bowel, for example, 

 maltose is converted into dextrose; cane sugar, into dextrose and lévu- 

 lose: proteins are broken down into peptones and albumoses, and 

 these again into leucin, tyrosin, and arginin: fats are converted into 

 fatty acids and glycerine. The columnar cells of the intestinal villi 

 have the power of recombining these substances into neutral fats. 

 Experimentally, an animal may be fed on fatty acids, and the intestinal 

 epithelium will synthesize them into fats and even supply the glycerine 

 for the purpose. Fatigue is also a problem in organic chemistry. 

 Owing to the overaction of muscle, certain degradation products, or 

 katabolites, as they are called, accumulate in the tissue fluids, pass 

 into the general circulation, and produce systemic effects. These 

 "fatigue" toxins, it can hardly be doubted, are of chemical nature. 

 Animal heat is not physical, not due to friction or condensation of 

 gases, but due to oxidative processes of various kinds. Vital sub- 

 stance also behaves as a chemical substance in that it is affected in 

 the same way by alterations in temperature. Chemical unions and 

 double decompositions, which are possible at ordinary temperatures, 

 are often suppressed altogether at a low temperature. Chemical re- 

 actions may be accelerated by heat: vital processes are hastened 

 similarly . As a concrete example of the effect of temperature we 

 may take the experiment of subjecting living bacteria to the tem- 

 perature of liquid air ( — 190° C.) or of boiling hydrogen ( — 273° C). 

 Under such conditions the bacteria in question can hardly be called 

 "living," in that there is no interchange of elements with the outside 

 world, no production of heat, water, or carbon dioxide: nor can they 

 be "dead," for they may be resuscitated to their peculiar functions 

 by restoring them to a usual temperature. We must recognize here, 

 as it were a condition of potential or latent life. The supreme import- 

 ance of chemistry in this connection will be realized when I make the 

 statement that the existence of animal life on this planet is directly 

 dependent on the presence of one chemical element — phosphorus. 

 The nucleus is the directing "brain" as it were of the cell. Without it, 

 while metabolism may continue for a time, growth and reproduction 



