CHAPTER XIII. 

 accidents. 



Street Nail Pricks. 



The "picking up" of street nails occurs chiefly to urban 

 work horses, of which it is the most common of all accidents. 

 In rural horses and in cattle it occurs more rarely. 



Nails penetrate any part of the solar aspect of the foot, 

 but the most delectable place is the region of the frog, espe- 

 cially in the lateral lacunae one inch from the point. In 

 depth the penetration is likewise varied. Most nails only 

 perforate the horn and velvety tissue, their course being de- 

 flected or arrested by the more firm overlying tissues, — the 

 bone and plantar aponeurosis. When the latter is perforated 

 formidable complications in the form of thecal or articular 

 abscesses usually follow. The character- of the infection also 

 varies, from feebly virulent pyogenic microbes which pro- 

 voke only a local and trivial suppuration to highly virulent 

 death-dealing bacteria, whose presence in the velvety tissue 

 is soon announced by a threatening, advancing inflammation 

 that may prove fatal in a few days. Tetanus and malignant 

 cedema are amongst the infections that are sometimes inocu- 

 lated into the foot by nail pricks. 



The seriousness of nail pricks depends, therefore, upon 

 (i) the depth and the course of the puncture, (2) the nature 

 and virulence of the infection, (3) resisting powers of the pa- 

 tient, (4) the soundness and conformation of the foot, and 

 finally upon the promptness with which proper treatment is 

 employed. 



PREVENTIVE TREATMENT. -Nail pricks may be 

 prevented by the application of a protecting plate that covers 

 the solar surface. Thin sheet iron, sole leather or several 

 layers of heavy canvas are the materials usually employed 

 for the purpose. Although these are not entirely impene-. 

 trable, even the latter (the softest of the three) is almost 

 universally preventive, because the mechanism which facili- 

 tates the "picking up" of nails is thereby destroyed. The nail 

 lying flat upon the street is tipped against the frog by the 

 toe of the shoe striking its head, and as the foot is simulta- 



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