D.—Effects of Venom in Non-Lethal Doses.
When the quantity of venom introduced into the organism is insufficient to cause death, the phenomena that precede and accompany recovery differ very greatly according as the snake from which the venom was derived belongs to the Colubridæ or Viperidæ.
After a non-lethal bite from a Cobra or Krait, for example, convalescence usually takes place very rapidly, and, apart from the local œdema of the subcutaneous tissue surrounding the wound, which in very many cases leads to the formation of a suppurating abscess, no lasting injury to health is observed. The venom is eliminated by the kidneys, without even causing albuminuria, and sensation gradually returns, in twenty-four or forty-eight hours, in the part affected by the original lesion.
If the bite has been inflicted by a Viperine snake, the local lesion, which is much more extensive, almost always results in the formation of a patch of gangrene. Hæmorrhages from the mucous membranes, and sanguineous suffusions into the serous cavities, such as the pleura or pericardium, may supervene more or less slowly. Pulmonary infarcts are sometimes produced, as well as desquamation and hæmorrhage from the kidneys, albuminuria, or hæmaturia. These lesions, which are more or less severe, last for several days, and then slowly disappear after a period of true convalescence. In many cases they leave behind them traces which last for months and even years, and they then more or less affect the health of the subjects according to the organs that were most seriously affected.
In certain cases, in domestic animals such as dogs, and more rarely in man, after recovery from the bite of a viper, total or partial loss of sight, smell, or hearing, has been observed. Such results, however, are fortunately exceptional.