IV] STRUCTURE OF THE CELL 161 



But we are by no means necessarily in this dilemma. For 

 though we come perilously near to it when we contemplate the 

 lowest orders of magnitude to which life has been attributed, yet 

 in the case of the ordinary cell, or ordinary egg or germ which is 

 going to develop into a complex organism, if we have no reason 

 to assume or to believe that it comprises an intricate " mechanism," 

 we may be quite sure, both on direct and indirect evidence, that, 

 like the powder in our rocket, it is very heterogeneous in its 

 structure. It is a mixture of substances of various kinds, more 

 or less fluid, more or less mobile, influenced in various ways by 

 chemical, electrical, osmotic, and other forces, and in their 

 admixture separated by a multitude of surfaces, or boundaries, at 

 which these, or certain of these forces are made manifest. 



Indeed, such an arrangement as this is already enough to 

 constitute a "mechanism"; for we must be very careful not to 

 let our physical or physiological concept of mechanism be narrowed 

 to an interpretation of the term derived from the delicate and 

 complicated contrivances of human skill. From the physical 

 point of view, we understand by a "mechanism" whatsoever 

 checks or controls, and guides into determinate paths, the workings 

 of energy; in other words, whatsoever leads in the degradation 

 of energy to its manifestation in some determinate form of ivorh, 

 at a stage short of that ultimate degradation which lapses in 

 uniformly diffused heat. This, as Warburg has well explained, is 

 the general eflect or function of the physiological machine, and in 

 particular of that part of it which we call "cell-structure*." 

 The normal muscle-cell is something which turns energy, derived 

 from oxidation, into work; it is a mechanism which arrests and 

 utiUses the chemical energy of oxidation in its downward course ; 

 but the same cell when injured or disintegrated, loses its "use- 

 fulness," and sets free a greatly increased proportion of its energy 

 in the form of heat. 



But very great and wonderful things are done after this manner 

 by means of a mechanism (whether natural or artificial) of 

 extreme simplicity. A pool of water, by virtue of its surface, 



* Otto Warburg, Beitrage zur Physiologie der Zelle, insbesondere iiber die 

 Oxidationsgeschwindigkeit in Zellen; in Asher-Spiro's Ergebnisse der Physiologie. 

 •XIV, pp. 253-337, 1914 (see p. 315). (Cf. Bayliss, General Physiology, 1915, p. 590). 



T. G. li 



