VARIATIONS AND MODIFICATIONS OF ABSOKPTION. 465 



fined in distinct portions of the intestinal canal of a living 

 animal do not present any marked variations in the rapidity 

 of their absorption, and they are taken up by the blood, even 

 when their density is greater than that of the blood-plasma. 

 Solutions of nitrate of potash and sulphate of soda of greater 

 density than the serum, which would, therefore, attract the 

 endosmotic current in an endosmometer, are readily taken 

 up by the blood-vessels in a living animal. 1 Indeed, nearly 

 all soluble substances, whatever be the density of their solu- 

 tions, may be taken up by the various absorbing surfaces 

 during life. 



The woorara poison and most of the venoms are remark- 

 able exceptions to this rule. In a series of very interesting 

 experiments upon the absorption of woorara, Bernard has 

 shown that this curious poison, which is absorbed so readily 

 from wounds or when introduced under the skin, generally 

 produces no effect when introduced into the stomach, the 

 small intestine, or the urinary bladder. This result, how- 

 ever, is not invariable, for poisonous effects are produced 

 when the agent is introduced into the stomach of a fasting 

 animal. 2 This peculiarity in the absorption of many of the 

 animal poisons has long been observed ; and it is well known 

 that flesh of animals poisoned with woorara can be eaten 

 with impunity. It is curious, however, to see an animal 

 carrying in the stomach without danger a fluid which would 

 produce death if introduced under the skin ; and the ex- 

 planation of this is not readily apparent. The poison is 

 not neutralized by the digestive fluids, for woorara digested 

 for a long time in gastric juice, or taken from the stomach 

 of a dog, is found to possess all its toxic properties, as we 

 have frequently shown (repeating the experiment of Ber- 

 nard) by poisoning a pigeon with woorara drawn by a fis- 

 tula from the stomach of a living dog. If we recognize the 



1 LOXGET, Traite de Physiologic, Paris, 1861, tome L, p. 921. 



2 BERNARD, Lemons sur les Effets des* Substances Toxiques et Medicamenteuses, 

 Paris, 1835, p. 282 et seq. 



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