Pharmacodynamics of Salts and Drugs 



107 



complete. If we assume it to be only 50 per cent, it would bring the 

 mercury into its proper position. Similarly with cadmium, which is 

 a trifle too low in its toxicity, this dissociation is certainly incomplete. 

 As regards cobaltous chloride, which is noticeably below what it 

 should be, I have no explanation to offer except to point out that it 

 occupies the same exceptional position toward some other forms of 

 protoplasm. Possibly its power of forming double compounds with 

 ammonia and its derivatives may have something to do with its 

 anomalous behavior. 



The constancy of K must be regarded, I think, with the exceptions 

 just mentioned, as satisfactory, when it is remembered that the method 

 of determining the minimum fatal dose — that is, by dilution — does 

 not permit of very accurate figures. 



C evaluated from these figures was — 4.1 11. (See Formula 4.) 



TABLE 6. 

 Resui.ts on Fundulus Eggs. 



Salts Compared 



CuCh-MnCU 

 HgCl,-MnCl, 

 HgCl,-CuCU. 

 NiCl,-MnCh 

 CoCU-MnCl, 

 HgCh-MgCl, 

 CuCl,-MgCl, 

 CuCU-NiCl, . 

 HgCh-CoCl,. 



■547 



. a6o 



.269 



473 



131 



.964 



. 120 



655 



• 367 



Mean value K=2.iq 



TABLE 7- 

 Comparison of Zn with all Other Metals. 



Salts Compared 



ZnCl, ■ 



ZnCl, ■ 



CdCU ■ 



CoCU - 



NiCU ■ 



PhCU - 



CuCU - 



HgCU • 

 AgNOj 



■MgCl, 

 -MnCh. 

 -ZnCl,. 

 ■ZnCl,.. 

 -ZnClj . 



ZnCI,.. 

 -ZnCU.. 



ZnCl,.. 

 -ZnCl. . 



(£>£:-<-<) 



0.726 

 0.302 



345 

 0.54' 

 0.546 

 0.613 

 1 . 102 



1 514 

 1.597 



log 



V. 



602 



301 

 194 



5051 

 2041 



795 

 2 73 

 7950 

 097 



.581 

 .610 

 .461 



934 

 .374 

 .296 

 .182 

 .186 



3"4 



Mean K a .03 



The results obtained upon Fundulus (Tables 6 and 7) do not give 

 quite such constant values as those of McGuigan, and indeed with so 

 complex a system this was not to be expected. However, the 



