10 ARSENIC IN PAPERS AND FABRICS. 



grain of arsenic per square yard no arsenic was set free either as a 

 volatile compound or as a dust during the course of seven days. 



In 1893 Gosio published a paper upon the "Action of some molds 

 upon the fixed compound of arsenic. " a This is the most important 

 article that has ever appeared upon the probable formation of vola- 

 tile compounds of arsenic from arsenical wall papers, and serves as a 

 basis for our present conception of this subject, which is so important 

 from a hygienic standpoint. The outline of Gosio's work is as follows : 



(1) To determine whether a gaseous compound of arsenic can be 

 developed by means -of cultures containing arsenic and exposed to 

 spontaneous inoculation. 



(2) If the affirmative be proved, to isolate the organisms which are 

 capable of so doing and to characterize them. 



(3) To point out the compounds in which this activitj^ of arseno- 

 organisms is most marked and to determine whether this activity 

 extends to arsenical products employed in the arts and industries 

 (colors), and what conditions cause the organisms to increase or 

 decrease. 



(4) To study the volatile compound, using pure cultures with 

 arsenical media. 



(5) To study the means by which these gases are produced. 



The results of these investigations are contained in the following 

 summary: 



It is confirmed beyond dispute that the growth of molds in contact 

 with fixed arsenical compounds can develop arsenical gas. Among 

 the molds some play this role in such a way that they may be consid- 

 ered as a special class of arseno-molds. 



There are four molds which up to the present time have been 

 shown to be capable of energetic action upon fixed arsenical com- 

 pounds, viz, Mucor mucedo, Aspergillum glaucum, Aspergillum virens, 

 and Penicillium brevicaule, the last being the most important. It 

 does not follow that because an organism grows well in the presence 

 of fixed compounds of arsenic it will produce arsenical gas. A large 

 number of the organisms flourish without producing this decompo- 

 sition. 



The arseno-molds can grow very well in contact with certain arsen- 

 ical compounds without actively transforming them. The action 

 depends on the salt used. For example, in the experiments upon 

 Mucor mucedo the action was very doubtful for the sulphides of 

 arsenic, and this doubtless depends on the insolubility of the material. 

 In all cases an exception must be made to the general law just enun- 

 ciated under the following conditions, namely : When the compounds 

 just mentioned have been in culture for a long time, by virtue of 

 indirect forces inherent in the life of the molds themselves their 



"Archives Italiennes de Biologie, 1893, vol. 18. 



