REVIEWS — Taylor's treatise on poisons. 413 



Reinsch's test as recommended by tlie author, and at the conclusion of 

 the paper, brought forward the preliminary evidence in the Smethurst 

 case, as a confirmation of his views, inasmuch as a solution was ex- 

 amined for arsenic, a number of times without success ; and the poison 

 was only discovered after repeated operations. "We formerly gave great 

 credit to Drs. Taylor and Odling, for their perseverance and skill in 

 detecting arsenic under such circumstances, a proceeding which is only 

 rendered difficult, by a bigoted adherence to one method of treatment. 

 "We then intimated that the non-detection of arsenic must have been 

 owing to some other mysterious agent than chlorate of potassa. The 

 mystery has since then been cleared up ; the fact being, that there was 

 no arsenic present, except such as existed in the copper employed, and 

 was dissolved during the progress of the experiment. 



Herapath has well observed, that no ordinary copper could possibly 

 contain such an amount of arsenic as was found by Dr. Taylor ; this 

 is undoubtedly true, but on the other hand it is well known, that no 

 reliance is to be placed on the method adopted by Dr. Tajdor for 

 ascertaining the quantity present. 



In the evidence given at the trial which has since taken place, it 

 appears that arsenic was detected in a portion of an evacuation, but it 

 must be remembered that the same copper was employed and that 

 nothing is said concerning the absence of nitrates, chlorates, &c. 



In some of the articles which have appeared in recent English news- 

 papers on the subject, doubt is thrown on chemical evidence as to the 

 presence of poisons. In the case of arsenic and all mineral poisons, we 

 most decidedly object to this opinion ; there is no difficulty and no 

 uncertainty affecting our decision on this subject, if proper precautions 

 be adopted, and if we do not refuse to avail ourselves of the results of 

 recent and accurate investigations. 



In a late number of the Philosophical Magazine, Davy has shown 

 that arsenic is present in the superphosphate of lime, used as a manure, 

 owing to the employment of impure sulphuric acid in its preparation. 

 He has also detected it in turnips grown on soil treated with this 

 manure, and in peas grown in mould moistened with a solution of ar- 

 senious acid. 



The test employed in all cases, was however, that of Reinsch, and 

 the copper may have contained arsenic. Davy states that the reagents 

 were proved to be pure, but as in the principal experiment, the copper 

 was boiled with the acid for three hours, and as we know from Odling's 



VOL. IV. DD 



