ARSENICALS. 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, (b) its symptoms are 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. 
Blvthe (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 death. 
According to the textbooks on pharmacology by Cushny (14) and 
Sollmann (49) j arsenic is termed, among other things, "a, capillary 
poison. " These authors state that arsenic is toxic to all animals 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 slowlv 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. cuneo) 
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 carminic- 
acid and carmine revealed pinkish intestines, those colored with the 
carmine being almost red. The intestinal contents of these larvse 
were pink, but no carminic-acid could be observed outside the 
intestinal wall. In the larvse fed carmine the stain was widely 
distributed. The nuclei in the cells of the intestine were strongly 
