2 INTRODUCTION 



and in association with living matter. When I was at school 

 they used to tell me that a verb indicated "being, doing or 

 suffering" and this certainly describes "life," though it does 

 not define it. " Och, life's aye a laugh and a greet," as Sir Harry 

 Lauder tells us. And then there's the well-known character 

 who defined life as "one d — d thing after another"; but he 

 was referring to a span of life — " Brief life is here our portion." 

 It was probably the same pessimist who said, "The moment 

 you're born, you're done for." For 



Life lives on death ; Death lives on life ; 



And so the circle runs, 

 Throughout a million teeming years, 



And half a million suns. 



Perhaps the best way to describe life is to enumerate those 

 qualities which living organisms have and non-living objects 

 have not, and then to say that life is the expression of these 

 qualities. In the " Introductio " to his Philosophia botanica 

 (1751) Linnaeus, who had named more plants and animals 

 than anyone since Adam, states : Lapides crescunt. Vegetahilia 

 crescunt & vivunt. Animalia crescunt, vivunt, <& sentiunt, and 

 roughly speaking this is true. 



Protoplasm 



Living matter or, as Huxley phrased it, the "physical 

 basis of life," is a substance called by Hugo von Mohl 

 protoplasm. Since this protoplasm is always being added to 

 from the outside world in the form of food and oxygen, and 

 per contra is always giving up something to the outside world 

 in the form of carbon dioxide breathed out and of other 

 excreta, some might regard it more in the light of a sj^ace, 

 in which various elements enter, combine, disintegrate and 

 take their exit, than as a substance. Still, for the convenience 

 of this book we will regard it as a substance never constant 

 in composition for a single second. 



To see this protoplasm in any mass and to form &ome idea 

 of what the substance looks like it is better to study some of 

 the larger of those animals which have but a single cell, or 

 the contents of some of the larger cells among the plants, for 



