CAUSES OF POISONING BY ARSENICAL PAPERS. 11 



chemical structure may be modified and thus they may be transformed 

 by the molds into gaseous arsenical compounds. 



The conditions which facilitate the production of arsenical gas by 

 the arseno-molds may be grouped as follows: 



'(1) Those conditions which favor the life of all fungi, namely, 

 abundance of oxygen, humidity, nutritive material, and amounts of 

 arsenic which are not toxic. 



(2) Such conditions as depend upon the ease with which the com- 

 pounds can be transformed. For example, arsenic acid and arsenates 

 and arsenites of sodium and potassium are more easily transformed 

 than copper arsenite. 



(3) Presence of carbohydrates and especially of mixtures of glucose 

 and albumen. 



In the experiments upon Mucor mucedo it was shown that the 

 arseno-molds can decompose the arsenite of copper used in wall paper 

 even when they grow upon the paste which is used to make the paper 

 stick to the wall. 



In the action of the arseno-inolds upon the fixed compounds of 

 arsenic, arsin may be developed, but only a small amount is formed 

 in comparison with the quantity of a much more important compound 

 which probably results from the combination of the metalloid with 

 alcohol, aldehyde, or other organic radicles. 



Without excluding the probability of some reducing and hydrogen- 

 ating action of certain molds upon traces of fixed arsenical com- 

 pounds, it is probable that in a great majority of cases the gasification 

 of such compounds is intimately associated with the development of 

 special chemical substances (the work of biological activity) capable 

 of combining with the metalloid. The power to form such compounds 

 is not possessed by all molds. 



These conclusions are based chiefly upon researches made on the 

 Mucor mucedo, but the Penicillium brevicaule is of much more im- 

 portance by reason of its biochemical activity and sensitiveness. 

 The cultures of this mold in the presence of fixed compounds of 

 arsenic develop the arsenical gas in such quantities that it is danger- 

 ous to approach. A rat upon being exposed to these gases died in 

 convulsions in a very short time. 



In the number of the Archives Italiennes de Biologie mentioned 

 above, on page 299, Gosio discusses the detection of arsenic in wall 

 paper, dress goods, the stomachs of animals, etc., by growing Peni- 

 cillium brevicaule in contact with these substances and a suitable 

 medium for growth and observing the garlic-like odor that is given 

 . off. The following paragraphs from this paper are worthy of particu- 

 lar note in connection with a study of arsenic in wall papers: 



I experimented upon wall papers colored with Scheele and Paris greens, realgar, 

 and orpiment, with the result that the Penicillium brevicaule, unlike other arseno 

 molds, attacked all the ordinary compounds of arsenic energetically (arsenic and 





