754 



SCIENCE 



[N. S. Vol. XLIII. No. 1117 



conditions and varying concentrations as pro- 

 tective or destructive agents, exhibit similar 

 abnormalities when tested by means of the 

 drop system described above. MgCl„ for ex- 

 ample, when employed in a drop system in con- 

 junction with Wa oleate, lowers the number of 

 drops, exerting an antagonistic effect against 

 NaCl virtually the same as that exerted by 

 CaCl.. When employed in a JSTaOH system, 

 the MgCl, acts like ISTaCl, causing however a 

 far greater rise in the number of drops than 

 NaCl. This effect may be counteracted by 

 means of CaCl, in proportions varying accord- 

 ing to circumstances from one of CaClj to one 

 to four of MgCl.. Anesthetics generally exert 

 an effect like salts of Ca, and counteract the 

 destructive effect exerted by N'aCl on the film, 

 but, under certain peculiar conditions and at 

 considerably higher concentrations, they may 

 exhibit a destructive effect on the film, caus- 

 ing an increase rather than a decrease in the 

 number of drops. This result is of interest in 

 view of the observation made by Lillie that 

 anesthetics exert protective effects on Arenicola 

 larvEe at certain concentrations, and destruc- 

 tive effects at other concentrations; partic- 

 ularly since the proportions in which given 

 anesthetics exert an optimum protective effect 

 on the drop film in our experiments, as indi- 

 cated by the minimum number of drops, ap- 

 pear to correspond fairly closely with those ob- 

 served by Lillie. These somewhat remarkable 

 effects are being studied further in the hope of 

 securing an insight into the exact nature of the 

 mechanism involved. These experiments indi- 

 cate that anesthesia is due to a diminution in 

 the permeability of protoplasm. If the rela- 

 tive effects exerted by monovalent, divalent and 

 trivalent cations are compared, it is found 

 that Ca exerts from twenty to thirty times as 

 great a protective effect on the film as ISTa, and 

 Fe from 100 to several hundred times as great 

 a protective effect as ISTa. Mono-, di-, and 

 trivalent anions exhibit similar but less readily 

 recognized ratios. Acids and alkalies exhibit 

 the same peculiarities in these systems as in 

 biological and colloidal systems, the H and OH 

 ions being apparently much more active than 

 other monovalent ions, and, in certain cases, 



exhibiting a greater activity than di- or tri- 

 valent ions. Weak acids and weak bases exert 

 far less effect than strong acids and strong 

 bases, and the ratios correspond fairly well 

 with the probable concentration of the H or 

 OH ion. The fact that ISTH.OH exerts vastly 

 less effect that N'aOH, while in biological sys- 

 tems NH^OH penetrates the protoplasm far 

 more readily than ISTaOH, is readily explained 

 when we remember that the penetration of 

 NaOH depends upon a destructive effect ex- 

 erted upon the protoplasmic structure resulting 

 in an actual increase in the permeability of the 

 system to water-borne substances, while 

 NH^OH presumably penetrates the proto- 

 plasmic system on account of its being dis- 

 persed or dissolved to a certain extent in the 

 non-aqueous phase. 



A single experiment has been selected from 

 a comparative series carried out on animals, 

 on the blood coagulation process, and on the 

 drop system, in order to show that antagonistic 

 electrolytes exert comparable effects in phys- 

 ical and biological systems. CaCl, and Na 

 citrate were selected for this purpose, not be- 

 cause similar results could not have been ob- 

 tained by the employment of OaOlj and N"a01, 

 but because the high concentrations of IfaCl 

 required would have exerted a disturbing 

 effect. By mixing a M/10 CaCl^ solution with 

 a chemically equivalent citrate solution in 

 varying proportions, it was ascertained that 

 they exert a compensatory or balancing effect 

 upon one another in the various systems de- 

 scribed, when present in the proportions of 

 approximately one equivalent of CaClj to two 

 equivalents of Na citrate. CaClj in excess of 

 this proportion gave a nmuber of drops less 

 than that given by the original system, Na 

 citrate in excess of this proportion gave a 

 larger number of drops, but when CaCl, and 

 the equivalent citrate solution were employed 

 in ratios of 1:2, the number of drops ob- 

 tained corresponded closely with that given 

 by the original system. When the same solu- 

 tions were injected into the tail veins of mice, 

 it was found that the fatal dose of either the 

 CaCL or citrate solution alone was from .25 to 

 .3 c.c. The amount required to cause the death 



