14 BULLETIN 1369, U. 8. DEPARTMENT OF AGRICULTURE 
properly drained they may discharge for considerable periods, and 
sometimes large encystments occur which may form a permanent 
blemish on the animal. 
Another injury of distinct type, but directly connected with the 
infestation with grubs, has been discussed by Hadwen and Bruce 
(39). They have shown that the injection of the juice of a few 
grubs into a bovine may cause death by anaphylactic shock in a 
few minutes, and that the crushing of a number of grubs in the back 
of an animal may cause marked anaphylactic symptoms. Their ex- 
planation of this is that when an animal has. been infested with 
larve of Hypoderma it becomes sensitized, and if the contents of 
erubs are introduced either by absorption through natural crushing 
of the larve in the back or by injection into the animal, anaphylactic 
symptoms are produced. In nature cases of anaphylactic shocks 
are probably rather rare, though they might follow the crushing of 
a considerable number of larve in the back of an animal, as some- 
times happens. 
In addition to the direct effect of the larve on the host itself, 
there is also an influence on the value of the meat as human food. 
The presence of the larve in the connective tissues of the back pro- 
duces a very repulsive if not actually injurious condition in that 
portion of the carcass.* This necessitates the trimming off of the 
affected parts, frequently resulting in the loss of 2 pounds of meat 
and at best leaving the carcass unattractive and hence less salable. 
This infiltrated edematous tissue is yellowish and more or less 
bloody, and appears watery or jelly-hke. It is seldom that more 
than the connective tissue and fat immediately under the skin are 
affected. 
The loss in the value of hides due to the holes cut by the larve 
is one which can be more nearly figured in dollars and cents than any 
other. Furthermore, this loss is constantly brought to the attention 
of hide dealers. Some very interesting information has been gleaned 
from the replies of about 100 packers, butchers, hide dealers, and 
tanners in all parts of the country through a questionnaire sent out 
in 1920. It has been computed from these replies that 19 per cent of 
all hides handled are classed as “ grubby ” and over 50 per cent of 
the hides taken off in grub season are so classed. The method of 
classing grubby hides varies considerably in different sections of 
the country. Most packer hides are sold on a grub-selection basis. 
The percentage of grubby hides is determined by the individual 
inspection of a sample of each lot of hides. Any grub injury which 
will permit of a skewer being pushed through is considered a grub 
hole. Country hides are usually sold “flat for grubs;” that is, the 
percentage of grubby hides is not determined by inspection, but the 
price is reduced during the grub season sufficiently to cover the low- 
ered value of the hides. ) 
On the Chicago market it is the custom of the trade to inspect, for — 
grubs, branded cow hides and Texas steer hides from November 1 to 
June 1, Colorado steer hides from December 1 to June 1, and all 
other classes except bull hides from January 1 to June 1. It is ob- 
vious that these periods do not fully cover the seasons of grub dam- 
age; for instance, in the Northern States where H. bovis occurs, 
some grubs are present throughout the summer. Bull hides and calf- 
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