1906.] The Chemistry of Globulin. 141 



applying this theory to the chemistry of globulin, it will be helpful to discuss 

 with its aid the remarkable connection, discovered by Schulze and investi- 

 gated by Picton and Linder, between the valency of ions and their coagulating 

 power. Hardy has shown that a similar relation holds for certain organic 

 colloids. A theoretical explanation of it has been offered by Whetham,* 

 based upon considerations as to the probability of electrolytic ions of like 

 sign coming together. Though suggestive, this theory seems to me inade- 

 quate, because the electric repulsion between ions of like sign tends 

 powerfully to keep them apart. On the present theory, coagulation 

 consists in opening out ineffective doublets $b so that they link together 

 neighbour molecules of the coagulating substance. Hence ionic charges must 

 sometimes be instrumental in coagulation, because a free jf tending to 

 attract b in the doublet and to repel b is an agent for opening out ineffective 

 doublets. Suppose that a free $ unites with b from an ineffective f b of a 

 molecule of coagulee, then it liberates jf, which will grasp the b of % neigh- 

 bouring ineffective jfb, and so the coagulation spreads until perhaps the other 

 ion of the electrolyte with its electron b steps in and arrests the process. But 

 there is another way in which coagulation can be propagated from an ion as 

 centre. The electric force of the ion will act on the ineffective doublets out 

 to a considerable distance from itself, and, moreover, every ineffective doublet 

 which is made chemically effective alters the local electric equilibrium by the 

 change. Each coagulated molecule is a centre of coagulation. Hence we 

 have the speed of coagulation due to an ion proportional to the electric 

 charge of the ion and to the amount of coagulation already produced by it. 

 Let c be the coagulum produced by electrolyte of concentration s, then we 

 have, with v for valence of the effective ion and k a constant, 



Tt W = hv h " log c t Co = kv ^""^ (11) 



where c is the amount of coagulum produced at a certain short time t after 

 the beginning of the process. This small initial coagulation is produced 

 mostly by the first process of direct linking, and is proportional to vs the 

 total number of electrons which start the linking up, so we may write 



log c/vs=kv(t-t' ). (12) 



Now, in the experiments, the number of equivalents vs of electrolyte 

 required to produce a certain amount of coagulation c in a very short time 

 are measured. We may neglect t' and take t as well as c to be the same 

 for each electrolyte. If we call ifvs the coagulating power of the electrolyte, 

 equation (12) makes its logarithm linear in the valency v. Schulze found 

 * 'Phil. Mag.,' [5], vol. 48. 



