Jan. i 5,1925 Raw Onions as a Control Measure for Worms in Dogs 157 
effect on these worms. On theoretical 
grounds this might be expected, if one 
assumes that the position of the whip¬ 
worm in the cecum is such as to expose 
it to anthelmintic effects much less 
than in the cases of worms in the 
stomach and small intestines. We 
may assume that whipworms have 
little resistance to anthelmintics, as 
Hall has noted in a number of papers, 
since they are occasionally removed by 
relatively feeble anthelmintics if these 
drugs enter the cecum, assuming that 
their removal is due to establishing 
contact between the anthelmintic and 
the worms, and this low resistance may 
be correlated with the fact that many 
substances taken in by mouth are 
absorbed before reaching the ileo-colic 
or ileo-cecal valve, may be greatly 
diluted before they enter the cecum, 
or may pass into the colon without 
entering the cecum if they do reach 
the valve, in this way failing to establish 
contact or to establish it in adequate 
anthelmintic concentration. To arrive 
at more definite conclusions in regard 
to the effect of the onions on whip¬ 
worms, one must compare the number 
passed with the number present post¬ 
mortem. 
Dog. No. 654 passed 25 whipworms 
and had 314 post-mortem; passed 7 
per cent. 
Dog. No. 656 passed 9 whipworms 
and had 2 post-mortem; passed 82 
per cent. 
Dog No. 658 passed 0 whipworms 
and had. 3 post-mortem on the thirty- 
seventh day; passed 0 per cent. 
Dog No. 659 passed 96 whipworms 
and had 34 post-mortem; passed 74 
per cent. 
DISCUSSION 
The figures show that these dogs 
passed 0, 7, 74 and 82 per cent of their 
whipworms while on an onion diet for 
37 days in the case of 1 dog and 60 
days in the case of 3 dogs, the lowest 
figure being for the dog on the diet for 
37 days. In a general way one must 
conclude from these figures that a 
substance fed in such large amounts 
and for a period long enough to insure 
its entry into the cecum on many 
occasions, and then removes only 7 
per cent of the worms in 60 days in 
the case of one dog, is not a very useful 
or effective anthelmintic. The dogs 
passed 130 out of 483 whipworms, or 
about 27.5 per cent. 
Two other factors must be. taken 
into consideration. One factor is that 
of possible mechanical anthelmintic 
action in one case. In the case of 
dog No. 659 which passed 74 per cent 
of its whipworms, the feces frequently 
contained large amounts of straw and 
hair | and the passage of this coarse 
material was commonly accompanied 
by the passage of whipworms. The 
writers have often noted in fecal 
examination of dogs that whipworms 
commonly come away in the presence 
of hair, straw, excelsior and similar 
objects which appear to act as me¬ 
chanical anthelmintics. Hall (4) has 
noted the passage of whipworms in 
connection with the passage of bots 
fed to dogs and believed that the bots 
acted as mechanical anthelmintics. 
From the fact that whipworms are 
apparently never found normally de¬ 
tached in the intestine the writers 
believe that these worms attach at a 
given point in their early development 
and never change this location. The 
larvae apparently penetrate the mucosa 
by means of a buccal lancet not present 
in the adult. If a mechanical anthel¬ 
mintic detaches a whipworm it can 
not reattach; a whipworm detached 
is a whipworm lost. Dog No. 659 
showed a pronounced pica, indicated 
by the presence of straw and hair in 
the feces and in the digestive tract 
post-mortem. This may be correlated 
more or less definitely with the heavy 
hookworm infestation, as pica is re¬ 
ported for human hookworm cases, 
notably in the case of the clay-eaters 
of the southern United States. 
The other factor which must be con¬ 
sidered is the possibility that the worms 
passed represented in part individuals 
which had lived out their lives and were 
coming away spontaneously and with¬ 
out regard to the onions or other possible 
anthelmintic factors. Parasitic worms 
in the digestive tract appear to live a 
year or less in many cases. Post¬ 
mortem examinations of many animals 
the world over has indicated that in the 
case of many worm species the number 
of worms increases in the late spring 
and through the summer, that the in¬ 
festation may continue or increase into 
the fall, but that there is commonly a 
drop in the number present in late win¬ 
ter and early spring. In a very com¬ 
prehensive study of tapeworm inci¬ 
dence in 2,012 horses, Stroh (12) found 
a seasonal incidence; thus Anoplo- 
cephala perfoliata was least abundant 
in spring and became increasingly 
abundant in the fall. It is well known 
that stomach worms in sheep become 
troublesome in the late spring and in 
the summer, but are much less trouble¬ 
some in the fall and winter, and that 
sheep killed in the late winter and early 
spring will commonly show a much de¬ 
creased infestation. The onion-feeding 
