﻿14 BULLETIN lae^, tr. S. DEPARTMENT OP AGBICULTXTRE 



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 anaphjdactic 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 

 larvae of Hypoderma it becomes sensitized, and if the contents of 

 grubs are introduced either by absorption through natural crushing 

 of the larvae 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 larvSe in the back of an animal, as some- 

 times happens. 



In addition to the direct effect of the larvse on the host itself, 

 there is also an influence on the value of the meat as human food. 

 The presence of the larvse 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 

 bloodj^, and appears watery or jelly-like. 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 larvse 

 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 

 ihe 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 cla.sses 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- 



