There is probably no disease of known or suspected germ origin which may not be followed by disastrous or unexpected surgical complications, while even degenerative changes, for which as yet no theory of parasitism has been invoked, are followed by conditions which may call for serious surgical measures. _In other words, the surgical complications of any so-called non-surgical disease may loom up at any moment in any case._ CHAPTER XVI. POISONING BY ANIMALS AND PLANTS. Certain poisons or deleterious substances are introduced in various ways into the human system from without, some of which produce only symptoms of moderate intensity, while others are fatal. It is authentically stated that in India many thousands of individuals lose their lives every year as the result of the bites of poisonous snakes. In 1903 there were officially reported 23,164 deaths from this cause. Nothing approaching such injuries in frequency or intensity can be found in any other part of the world. Animal poisons may be introduced by animals of many species. The poison of hydrophobia has been described. The bites of the mammalia may be serious and may be followed by septic symptoms, but are not ordinarily regarded as due to any special toxin secreted by the animal. A number of reptiles, however, possess special _poison glands_ which are connected, in most of them, with a tooth on either side of the upper jaw which is canaliculated, and serves as a duct through which the poison is injected when the animal inflicts its bite. SNAKE BITES. The principal poisonous serpents in North America are the _rattlesnakes_--of which there are several species, usually placed at eighteen--the _copperheads_, the _moccasins_, and the _vipers_. Some of these have movable poison fangs, some fixed. In other parts of the world others equally or even more poisonous are known.