96 DYNAMICS OF LIVING MATTER 



lism. Respiration eliminates the CO^ in part, but there would be 

 danger that every organism would finally perish through its own produc- 

 tion of acid were these acids not constantly neutralized. This is partly 

 done by the carbonates of the blood. The proteids of the blood are 

 also capable of neutralizing a considerable amount of acid by com- 

 bining with it,* and I believe this r61e of the proteids in the blood should 

 not be overlooked. The fact can be demonstrated in a striking manner 



by putting a frog's muscle into loo c.c. of ox blood, to which lo c.c — 



n ^° 



HCl or lo c.c. — NaHO have been added. The muscle does not absorb 



lO 



water in such a solution, and remains ahve for several days. If the 

 muscle be put into an isotonic solution of looNaCl, 2 CaCl,, 2 KCL, to 

 which the same amounts of acid or alkali are added, the muscle absorbs 

 considerable quantities of water and dies rapidly. A third means of 

 keeping the reaction of the hquids of the tissues neutral is probably 

 the compensatory production of bases in the body, possibly induced by 

 the acids. 



It is easy to show that marine animals are able to develop and grow 

 only in such solutions as are capable of neutralizing the acids which 

 might be formed. If the polyp be cut off from stems of Tubularia crocea, 

 new polyps are formed in about two days if the temperature is about 

 20° C. As soon as the polyp is formed, growth begins. If a solution be 

 prepared of 100 molecules NaCl, 2 molecules KCl, 2 molecules CaClj, 

 7.8 molecules MgCl^, 3.8 molecules MgS04, isotonic with sea water, 

 the formation of polyps occurs more slowly than in sea water, and 

 growth is slight. If, however, to such a solution be added from 0.5 



to I c.c. — NaHCO, or o.i c.c. — Na,CO, or 0.2 to i.o c.c. of a — solu- 

 8 8 10 



tion of NaHO, regeneration and growth occur with normal velocity.f 

 These three substances have the property in common that they are 

 able to neutralize acids, and I am inclined to ascribe it to this peculiarity 

 that they are capable of accelerating growth in Tubularians. It har- 

 monizes with this view that NaHCOj acts better than NaHO. If, 

 however, a trace of acid instead of alkah is added to the original solution, 



growth is still more retarded. The addition of o.i to 0.15 c.c. — HCl 



solution to 100 c.c. of the above-mentioned solution suffices to suppress 



n 

 growth entirely ; this corresponds to a concentration of HCl of - — to 



* Bugarszky und Liebermann, Pfluger's Archiv, Vol. 72, p. 51, 1898. Spiro und Pemsel, 

 Zeitsch. fur physiol. Chemie, Vol. 26, p. 233, 1898. 

 t Loeb, Pfluger's Archiv, Vol. loi, p. 340, 1904. 



