202 PRINCIPLES OF GENERAL PHYSIOLOGY 



struction, physical and chemical, of the given organism. At the same time, he points out that 

 there are real adaptations. The capacity of an individual to react appropriately to his 

 environment has been brought about by the elimination of myriads of individuals who failed to 

 do so. Adaptation has been regarded as a sort of transcendental property of organisms, an 

 entelechy, allied to intelligence. But, as Parker remarks, what do we really mean by in- 

 telligence other than "that aggregate of nervous states and actions which is our chief means of 

 adaptation"? so that the proper understanding of adaptive reactions implies that of in- 

 telligence, and conversely. The introduction of such notions as entelechies consists, practically, 

 in argument in a circle and is rather calculated to retard progress by apparent explanation, 

 when what is really wanted is research into the very questions which they pretend to answer. 

 "The details of animal reactions are then, in the main, free from adaptive restraint and tlu-ir 

 diversity is dependent chiefly upon the fluctuating momentary condition of the animal iMidy : 

 further, the main outlines of animal reactions are adaptive, but are not to lie explained by the 

 assumption of something like intelligence." 



The effect of Rise of Temperature on hydrogen ion concentration is of some 

 importance. In a previous page the large temperature coefficient of electrolytic 

 dissociation of water was referred to in another connection, as being of the order 

 of those regarded as characteristic of chemical reactions. That of sodium salts, on 

 the other hand, is the very low one of salts in general, which do not obey the 

 Ostwald " dilution law." On mixtures of bicarbonate and CO., the net effect of a 

 rise of temperature will be to increase the alkalinity, since the dissociation of 

 water will be increased more than that of the bicarbonate. Thus water at 18 has 

 a dissociation constant of O64 x 10~ 14 , i.e., 



(C)oHx(C) H = 0-64x10-". 



A solution of sodium bicarbonate and CO.,, which has, at 18, a hydrogen ion 

 concentration of 0*30 x 10~", has accordingly a hydroxyl ion concentration of 



0-64x10-" , 1Q .. 



0-30x10-' - 



since the product of (C) OH . and (C) H . is constant in all solutions in water at the 

 same temperature. 



At 42, the hydrogen ion concentration of the bicarbonate mixture has risen 

 only to 0-42 x 10~", owing to its low temperature coefficient, whereas the 

 dissociation constant of water has become 3-76 x 10~ 14 (Kohlrausch and 

 Heydweiller, 1894, p. 209). Hence the hydroxyl ion concentration has risen to 



3-76 x 10- 14 



or 4-3 times as great as at 18. 



The proteins present in the blood and tissues play some part in the maintenance of 

 neutrality, owing to their amphoteric nature. They form salts with both strong acids and 

 strong bases, just as amino-acids do. But they do not readily form salts with weak acids or 

 bases and, as present in the organism, they themselves are but slightly dissociated. 

 L. J. Henderson (1909, p. 289) dialysed serum, in order to remove the bicarbonates and 

 phosphates, adding sodium chloride at intervals to keep the globulins in solution. It 

 was then found that a fairly large amount of sodium hydroxide required to be added 

 in order to change the colour of rosolic acid in the serum. The proteins are active 

 therefore in the same way as the bicarbonates and phosphates, but their part seems to be 

 a subordinate one and dependent on their high concentration rather than on their special 

 properties as acids or alkalies. They are, however, able to drive off carbon dioxide from 

 bicarbonates, owing to the fact that it is eliminated by the lungs as gaa, as it is formed. By 

 this removal from the reacting system, a very weak acid is enabled to decompose the bi- 

 carbonate. Suppose that there is produced even a very small increase of the HCO 3 ' in the 

 solution ; this increase involves that of the pressure of the dissolved CO a gas and escape of a 

 part of it. A further amount of HCO 3 ' is then formed by the weak acid, in order to hrini: 

 nack equilibrium, and thus the process continues. 



The Reaction of Blood. By the most sensitive methods available, the hydrogen 

 ion concentration of blood at 38 is found to be 0'4 x 10"" and the corresponding 

 OH' ion concentration, 7 '2 x 10"" molar. So that it is just on the alkaline side 

 of neutrality. At room temperature, the alkalinity would be somewhat less, owing 

 to the increase of OH' ion concentration in CO 2 bicarbonate systems with rise 

 of temperature, as described above. Direct measurements of the effect of 

 temperature on such systems, in moderately concentrated form, have shown 

 about four times as great an alkalinity at 38 as at 18. This is dependent on 



