324 ZOOLOGY. 



lizard, and the viper itself. A grain of the poison of the viper 

 will kill a sparrow, but it will require six times as much to 

 kill a pigeon. As the poison acts through the circulation, 

 the most rapid means must be adopted to prevent absorption, 

 such as washing with water and strong spirits, a ligature 

 round the part bitten, and, if possible, its excision. Ammonia 

 has been much celebrated as an antidote, but it cannot be de- 

 pended on. The Indians of South America consider as a 

 powerful antidote a plant called guaco, or micania guaco ; 

 they assert not only that the application of the leaves of this 

 plant to the wound prevents all dangerous effects, but that 

 the inoculation of the juice of the plant will prevent such 

 bites having any bad effects. Humboldt thinks that there 

 may be something in the odour of the plant which may pre- 

 vent the serpent from biting the person. The serpents with 

 fangs called moveable are the most dangerous; the fangs are not 

 in fact moveable, but attached to very small maxillary bones, 

 which are so. In general you find one fang fixed in either 

 side, with several others of different stages of growth, ready 

 to replace them when lost, which probably happens at regular 

 periods. The poisoned fangs are shed by a process analogous 

 to what takes place in the teeth of fishes. In the viper, 

 rattlesnake, cobra, and several others, the upper maxillary 

 bones carry poison fangs only ; and thus between them and the 

 common snake there is this marked difference, that the maxil- 

 lary and palatine bones in the upper jaw carry each a row of 

 teeth, giving an appearance of four rows to them, whilst in 

 the true poisoned serpents just mentioned we find only two 

 rows, the palatine only ; but in the venomous water snakes, 

 and in many others, the superior maxillary bones carry 

 simple teeth as well as the poisonous fangs. Some reptiles 

 have no teeth, such as the tortoise and turtle, a homy layer 

 like the bills of birds supplying their place. 



465. There is never any pendulous palate, and in most 

 the pharynx is not distinct from the mouth, nor the gullet 

 from the stomach. The intestines are short, and have no 

 caecum; the large intestine differs but little from the small, 

 and terminates in a cloaca, as in birds ; they have lymphatic 

 and lacteal vessels. 



466. We have already remarked that their blood is not 

 rich in globules, and that these are large and elliptic. The 

 disposition of the circulating apparatus varies ( 108), but, 

 as we have said, there is always a direct communication 



