444 Tetanus. 



dangerous in this regard, are injuries from nails, nail punctures 

 of the hoof or foot, about the coronary band, and particularly in- 

 juries about the lower portions of extremities ; fractures of bones, 

 wounds of castration, and harness galls; in horses tail docking; 

 furthermore injuries of the mucosa of the mouth (through carious 

 or sharp teeth) or genital passages (from aid in difficult labors), 

 in the newborn the contamination of the navel wound, in foals 

 the operation of umbilical hernia, injuries of the eyes, etc. In 

 any case the most varied injuries and accidents may give rise 

 to the disease provided that dead tissue, extravasated blood 

 or w^ound secretions facilitate the multiplication of the con- 

 tagion ; aside from this the penetration of the anaerobic bacillus 

 into the deeper portions of the tissue or into hidden cavities 

 or pockets of wounds favors the development of the disease. 



The infectious material gains entrance into the wound with 

 earth, necrotic tissue or wound secretion containing bacilli, or the 

 infection is facilitated by wood shavings, bone splinters, the har- 

 ness of a horse suffering with tetanus, or by hair ropes, manure 

 applied to a wound, further by implements, surgical instruments, 

 the hands of operators or those assisting them in operations. In 

 this w^ay, for instance, tetanus is conveyed after castration 

 through the medium of the operator 's soiled hands or by clamps 

 which had been used before, while in other cases the virus 

 reaches the castration w^ound from the horse lying down and 

 contaminating it. The cases wdiicli point to the first mode of 

 infection are those that occur among animals which have been 

 castrated by the same operator within a short period of time, 

 even though in different places, when cases of disease occur 

 in rapid succession. Those pointing to the second mode of 

 infection are the ones where year in and year out animals from 

 the same farm become diseased. Since the antiseptic treat- 

 ment of wounds, tetanus occurs much less frequently after 

 such operations which w^ere formerly considered dangerous 

 (castration with ligation of the spermatic cord, especially in 

 rams and calves). 



It is therefore possible to designate the site of infection 

 in most of the cases, but there are cases where even the most 

 careful examination fails to reveal an injury of the body surface 

 or of the mucous membranes. Such observations, which were 

 formerly considered rheumatic tetanus, make it probable that 

 the disease may occur exceptionally without any preceding 

 injury. This might be assumed in parturition tetanus in the 

 sense"^ that the infectious virus is propagated in the exudate 

 which collects in the womb and the toxins thus produced pass 

 from here to the hanphatic circulation. In this way could those 

 cases be explained where the occurrence of tetanus may be 

 associated wath the retention and decomposition of the placenta. 

 In many cases of horse tetanus it is impossible to exclude the 

 possibility that the contagion multiplies in the follicles of the 

 tonsils or between the folds of the intestinal mucosa to such 



