48 Causes of Disease. 



fectious agencies. The old idea that by causing a more or less 

 prolonged contraction of the cutaneous vessels the skin secretions 

 are reduced or prevented and that in this way there tend to 

 accumulate metabolic or other toxines in the tissues cannot be set 

 aside. Such substances have been thought to perhaps possess 

 irritant qualities which disturb the sensory nerves and muscle 

 fibres and other structures, the rheumatic pains and stiffness sup- 

 posedly arising in consequence. At least some weight is to be 

 given to the readiness of disappearance of such symptoms when 

 by warmth and exercise the general circulation is stimulated and 

 skin secretion heightened, these toxines then perhaps finding more 

 ready excretion from the body than could be afforded by the 

 other excretory paths.] 



Electrical Influences. 



Powerful electrical discharges upon the animal body induce 

 paralysis of the nervous apparatus (especially of the respiratory 

 centre), electrolytic destruction of the red blood cells, local 

 burns of the skin and laceration of the tissues. Death usuallv 

 follows ; but the paralysis and unconsciousness may, after shorter 

 or longer duration, go on to recovery. The larger animals (cat- 

 tle and horses in the stall or in the open) are especially liable 

 to be struck by lightning (Frohner, Ziegenbein). Contact with 

 live wires and completion of the circuit through the bodies of 

 horses occasionally takes place when they step upon the contact 

 points of an electric railway in the street pavements or on a 

 broken overhead wire.'"' Horses have been killed by a current 

 strength of 500 volts, 100 amperes (Puntigam, Mouquet, Blanch- 

 ard) ; alternating currents of 160 volts are sufficient to kill dogs 

 (Birch-Hirschfeld). 



According to Leblanc, horses are exceptionally susceptible to electricity. 

 A horse was killed, for example, by a relatively light current which the 

 owner passed through the bit in order to divert the attention of the animal 

 while being shod. 



Anatomical changes may be entirely absent when death has 

 been caused by electricity, or the hair may be found singed and 

 the skin burned by the electric spark ; and at the points of en- 

 trance and exit of the lightning or current, as well as in the 

 internal organs, the tissues may be lacerated, with which lesions 



♦Birds sit on telegraph wires witli Impunity because they are not in contact 

 with the earth. 



