june, '16] holland: detection of arsenic in bees 365 



Methods for Destroying the Organic Matter 



At the outset the organic matter in the samples was destroyed 

 with sulfuric and nitric acids. These agents were first suggested 

 to the writer by the late Dr. Goessmann in place of hydrochloric 

 acid and potassium chlorate formerly employed for the purpose in the 

 station laboratory. The process requires time and patience to insure 

 complete destruction of the organic matter but is satisfactory as a 

 whole and preferable to the old method. 



As the number of samples increased and the demand for an early 

 report became more urgent, an effort was made to improvise a process 

 to meet those conditions with the least possible interference with 

 regular work. An attempt at treating with potassium chlorate and 

 igniting (an old method for wall paper) proved impracticable, and 

 hydrogen peroxide proved inefficient as an oxidizer. Sodium peroxide, 

 potassium bichromate and potassium permanganate were also con- 

 sidered. The last appeared the most promising and could be used 

 readily as a saturated solution. The combined winter losses of two> 

 apiaries furnished a liberal supply of bees for experimental work. 



Method Employed 



Representative portions of the bees as received and with an added 

 amount of arsenous oxide or of arsenic oxide were macerated in a, 

 platinum dish with a saturated permanganate solution (20 c.c. to each 

 gram of material), evaporated to dryness, heated at a temperature not 

 exceeding faint redness, pulverized and reheated until the residue would 

 no longer "glow." The "crude" ash was transferred to a Marsh 

 apparatus with sulfuric acid (1-3) and gave, in cases of added arsenic, 

 a positive inside mirror. Several samples of suspected hay also 

 reacted with the above test; evidently due to heedlesss spraying of the 

 grass. Possibly permanganate has been used in this connection by 

 other workers as it is now employed for many oxidizing purposes in 

 most laboratories. Nevertheless, our method of procedure together 

 with results secured are offered in the hope that they may prove of 

 service. 



Toxic Dose of Arsenic for Bees 



So far as noted there have been no reliable data published as to the 

 toxic dose of arsenic for bees. The arsenical compounds generally 

 employed as insecticides are salts of lead, copper and lime. Although 

 lead and copper have toxic properties, arsenic should be considered 

 the active principle of the insecticide. Practical experience indicates 

 that a given weight of arsenic (As) in the form of arsenites (AS2O3) is 

 more poisonous than in arsenates (AS2O5). This appears to hold true 



