CAUSES OF POISONING LY ARSENICAL PAPERS. 13 



experiment was continued further, and about^O.ll milligram more of 

 arsenic was obtained from the two silver solutions. The silver-nitrate 

 solution that had been used to wash the incoming air was tested for 

 arsenic, but none could be found, showing that no arsenic could have 

 entered the flasks from the air of the room. 



In another experiment 3 square decimeters of wall paper containing 

 115 milligrams of arsenious oxide per square meter were placed 

 between slices of potato, and after sterilization in flasks similar to 

 those mentioned above they were inoculated with one of the Gosio 

 cultures. Without going into the details of the experiment, which 

 was similar to the one just described, it suffices to say that an alli- 

 aceous odor was developed and a mirror of arsenic obtained from the 

 silver-nitrate solutions. 



The papers by Gosio and Sanger just quoted establish beyond ques- 

 tion the fact that certain molds can set volatile compounds of arsenic 

 free from fixed compounds of this element, which may be present in 

 wall paper or other materials in case a suitable medium for growth is 

 present, such as the paste used in putting on wall paper. The fact 

 that PeniciUium brevicaule, one of the most active molds in producing 

 such effects, has been found upon moldy wall paper would almost be 

 proof of the formation of arsenical compounds in rooms papered with 

 arsenical paper. The work of Hamberg, who actually found volatile 

 arsenical compounds in rooms papered with arsenical paper, seems to 

 complete the chain of evidence. 



In 1896 a Emmerling made an investigation of the action of bacteria 

 and molds upon the fixed compounds of arsenic. He came to the 

 conclusion that neither of these classes of organisms could set arsenic 

 free as a volatile compound. In his work, however, he used such large 

 amounts of arsenic acid, i. e. , 0. 5 per cent and 0. 2 per cent, that it is pos- 

 sible, in fact probable, that the arseno molds were killed off. In his 

 original paper Gosio especially calls attention to the fact that these 

 molds are most active in media containing from 0.01 per cent to 0.05 per 

 cent of arsenic acid, and that as the media become stronger in arsenic 

 the activity of the molds becomes less intense until with quite large 

 amounts of arsenic the molds cease to grow entirely, unless they have 

 been habituated to arsenic by a progressive augmentation of this sub- 

 stance in the medium. Since Emmerling does not mention any of the 

 details of his experiment, we have no method of judging of the 

 accuracy of his determination of arsenic, etc. 



Having now established the fact that fixed arsenic can be set free 

 from organic substances containing this element as a gaseous com- 

 pound, or from wall papers containing it as a fine* dust, and that 

 arsenic in both these forms has been found in the air. of rooms the 

 walls of which were covered with an arsenical paper, it becomes neces- 

 sary, as the next link in the chain of evidence, to show that persons 



Ber. d. chem. Ges., 1896, 2J): 2728. 



