rHAHI,P:s HOHKHT SA.VGKH. 817 



of iin arsenical gas was his last contrihutioii to the study of poisoning 

 from wall papers, hecause he felt obliged to retire from the field in 

 order not to interfere with Gosio. This was eertainly unfortunate, 

 since his earlier work justifies the eon\icti()n that he would have 

 solved this problem also, if he had hot been eompeilcd to relinquish 

 the study of it. As it is, the mystery remains; Biginelli has found, 

 it is true, that the gas formed by the moulds is an arsine, a substance 

 related to the alkaloids and therefore probably more poisonous than 

 most other compounds of arsenic, but it has not been shown how this, 

 or any other gas can be formed from wall papers, which only in excep- 

 tional cases are in situations moist enough to fa\or the growth of 

 moulds. 



When in this way Sanger was shut out from the practical side of 

 this investigation, he turned his attention to the purely chemical side 

 of the work, extending his analytical method to the quantitative 

 determination of antimony; and later applying this system of deter- 

 mining the amounts of arsenic, or antimony to the method of Guth- 

 zeit, which in his hands became the most accurate and delicate method 

 known for such work, and even displaced his own earlier Berzelius- 

 Marsh process, admirable as that was. I think he considered this 

 the best piece of work that he did, but I must give the preference to 

 his work on arsenical poisoning from wall papers on account of its 

 great practical importance, and because in this connection he worked 

 out the general principle at the bottom of all these methods. 



Two important papers, which occupied the last years of his life, 

 belong to a tlifi'erent line of work. His object here was to prepare the 

 silicon compound corresponding to phosgene, a well known derivative 

 of carbon; but a reaction, which should have led to it in view of the 

 strong resemblance between these elements, gave different products, 

 the identification of which, simple as it seems at first sight, reciuired 

 an unusual amount of ingenuity, chemical insight, and skill in manipu- 

 lation. This research brought out the entirely imexpected fact, that 

 our knowledge of pyrosulphurylchloride and chlorsulphonic acid — 

 two compounds supposed to be thoroughly established — rested on an 

 inadequate experimental foundation, and in the first of these papers 

 accordingly he placed them on a secure basis with his usual faithful 

 accuracy. The skill in devising apparatus, and overcoming obstacles 

 shown in these papers adds to our regret, that he was not spared to 

 carry on other researches in this somewhat neglected field of inorganic 

 preparations. 



Among the work he left unfinished was a much needed method for 



