ABNORMAL CONSTITUENTS. 23 



sub-sulphocyanide of copper by the addition of the sulphates of 

 protoxide of iron and oxide of copper; as, however, the preci- 

 pitate never consists of pure sub-sulphocyanide of copper, we are 

 compelled to determine the sulphur as sulphate of baryta. 



The application of basic acetate of lead, according to Wright's 

 method, for the precipitation of the sulphocyanogen, is inapplicable 

 in this case ; for the sulphocyanide of lead is somewhat soluble in 

 water, and the greater part of it would probably be lost on washing. 



Abnormal constituents occur in the saliva probably more 

 frequently than in many other animal secretions. It is very 

 remarkable, that many mineral and organic substances which are 

 thrown off by the urine either unchanged or little modified, are 

 far more rapidly eliminated by the salivary glands often, indeed, 

 before they could be separated by the kidneys from the mass of 

 the blood. We may very readily convince ourselves of this fact, 

 by taking 5 grains of iodide of potassium in pills, when we shall 

 find that it can be much sooner detected in the saliva than in the 

 urine ; in the latter fluid we may very often easily discover it after 

 forty hours. 



Moreover, when iodine is applied externally, as, for instance, 

 in the form of ointment, it very rapidly passes into the saliva, 

 where it may be recognized by nitric acid and a solution of starch, 

 while it cannot be detected in the urine. 



When iodine has been taken in the form of pills, and we have 

 convinced ourselves, immediately after they have been swallowed, 

 of the absence of this substance in the buccal mucus and in the 

 saliva, we may very often detect it in the last-named fluid after a 

 lapse of ten minutes, while it will not appear in the urine for a 

 period varying from half-an-hour to two hours. 



Bromine and mercury, and probably several other sialagogues, 

 behave in this respect like iodine. 



The reason why these substances so readily excite the flow of 

 saliva, is probably solely dependant on the circumstance that 

 they are separated from the blood by the salivary glands. It is 

 possible that several organic sialagogues act simply in the same 

 manner, namely, by some of their constituents, like the iodine, 

 being readily separated by the salivary glands. 



Wright and several other observers have been unable to detect 

 any mercury in the saliva during mercurial salivation. I formerly 

 had many opportunities of examining the saliva in cases in which 

 salivation ensued during the treatment of syphilis by inunction 

 practised by Rust and Louvrier, and I constantly found mercury 



