170 PROCEEDINGS OF THE AMERICAN ACADEMY. 



could be found. Theu ^ grain (6.48 rngr.) was given for six days 

 more, and on the twelfth day r ^-g grain (0.52 nigr.) was recovered. 

 No attempt was made in any of the trials to follow the elimination 

 until it stopped. 



When we consider that the determination of the arsenic was made 

 by weighing the mirror obtained, and that the amounts varied from 

 0.35 rngr, to 1.12 rngr., the chances for error in weighing will be seen 

 to be very great. Furthermore, the evaporated urine was added 

 directly to the reduction flask, and Hubbard himself thinks that the 

 organic matter is apt to interfere with the reduction and accurate 

 deposition of the arsenic. 



This, besides being the only quantitative series of experiments that 

 I can find, concerns only the elimination when the arsenic is taken as 

 arsenious oxide. 



As to the rate of elimination, then, in cases of chronic wall paper 

 poisoning, there are, so far as I know, no other data than in my ex- 

 periments or in those of the historical sketch. Wood* has, however, 

 recently made an investigation into the length of time required for 

 elimination in cases where the poisoning occurred from other causes. 

 His results are not quantitative. Two of the cases were chronic (from 

 Fowler's solution), the third being acute (from arsenious oxide). In 

 the first two, 58 and 82 days were required, and in the third 93 days. 

 Wood also refers to a chronic case by Gaillard f (Fowler's solution), 

 in which 53 days were required. In the cases given above, though 

 the elimination was not examined to completion, the time after which 

 arsenic still appeared varied from 19 days to 140 days. 



But neither Wood's nor Hubbard's work enables us to draw 

 an inference as to the rate of elimination from such minute doses as 

 would come from a wall paper, and we have no parallel work what- 

 ever on the amount or rate when the arsenic is in the form of a deriv- 

 ative of arsenic acid. 



In discussing the source of chronic wall paper poisoning, we have 

 to consider in what state the arsenic compounds exist in the air of the 

 room. The possibilities are two: a gaseous or volatile compound, 

 and the solid particles mechanically detached from the paper. In 

 addition to the action of the arsenical dust in the air, we are now in a 

 position to consider the action of a volatile arsenical compound. The 

 formation of a volatile compound from decaying arsenical matter, first 



* Bost. Med. Surg. Journ., CXXVIII. 414. 

 t Ann. d' Hygiene, October, 1874. 



