﻿ABSBNICALS. 49 



were swollen, and they could not fly, although they could walk in a 

 staggering manner, dragging their abdomens on the table. The only 

 difference between the behavior of the bees subjected to nicotine 

 poisoning {29, p. 91) and that of bees subjected to arsenic poisoning 

 is that (a) nicotine acts more quickly, (6) its symptoms an; more 

 pronounced, and (c) in arsenic poisoning the abdomen is always 

 more or less swollen, while in nicotine poisoning the abdomen is only 

 rarely swollen. From the symptoms observed, it may be concluded 

 that the bees fed arsenic might have died of motor paralysis, although 

 the paralysis may be only a secondary cause. 



Blythe {4, p. 567) says that flies, within a few minutes after eating 

 arsenic borne on common arsenical fly paper, fall, apparently from 

 paralysis of the wings, and soon die. Spiders and all insects into 

 which the poison has been introduced exhibit a similar sudden deal h. 



According to the textbooks on pharmacology by Cushny {14} and 

 Sollmann (49), arsenic is termed, among other things, "a capillary 

 poison. " These authors state that arsenic is toxic to allanimals having 

 a central nervous system and also to most higher plants, but not to 

 all the lower organisms. In mammals arsenic is cumulative, being 

 stored in various organs, and it is excreted very slowly by the usual 

 channels — urine, feces, sweat, milk, epidermis, and hair. With oral 

 administration, the main part leaves by the feces, probably having 

 never been dissolved. 



TRACING ARSENIC IN TISSUES OF INSECTS. 



All attempts to trace arsenic fed alone to fall webworms {H. cunea) 

 by histological methods failed. The light-colored precipitate formed 

 by the union of arsenic and silver nitrate was either washed out of the 

 tissues or was obscured because the tissues were stained dark by the 

 silver nitrate. 



In an endeavor to trace arsenic in both the soluble and insoluble 

 forms by stains and lampblack the following experiments were per- 

 formed, using the method for tracing nicotine outlined by Mclndoo 

 {29, p. 106-109). 



Four sets of fall webworms were fed leaves sprayed with an acid 

 lead arsenate (sample 39), mixed with stains or lampblack as follows: 

 First set ate arsenate mixed with indigo-carmine; second set ate 

 arsenate mixed with carminic-acid ; third set ate arsenate mixed with 

 No. 100 carmine powder; and fourth set ate arsenate mixed with 

 No. 100 lampblack powder. A day later those fed carmine were voiding 

 reddish feces, and two days after being fed all of those nearly dead 

 were fixed in absolute alcohol. The indigo-carmine and carminic- 

 acid were soluble in water, but they were partially precipitated by 

 absolute alcohol; the carmine was only slightly soluble in water, but 

 totally insoluble in absolute alcohol; and the lampblack was soluble 

 in neither water nor absolute alcohol. 



Webworms fed indigo-carmine showed no stain. Those fed carmine- 

 acid and carmine revealed pinkish intestines, those colored with the 

 carmine being almost red. The intestinal contents of these larva? 

 were pink, but no carmine-acid could be observed outside the 

 intestinal wall. In the larvae fed carmine the stain was widely 

 distributed. The nuclei in the cells of the intestine were strongly 



