Section 3. 

 Absorption in General. 



The activity of absorption, especially in the horse, has been 

 made known to us by the experiments of Colin. 



Absorption from the Respiratory Passages is remarkably rapid. 

 Colin showed that potassium ferrocyanide could be detected in 

 the blood two minutes after being injected into the trachea, and 

 that it appeared in the blood before it was found in the chyle ; 

 the same salt was also found in the urine eight minutes after 

 being introduced into the trachea. A solution of nux vomica 

 injected into the trachea produced tetanic symptoms in three 

 minutes ; turpentine, alcohol, and ether were also rapidly 

 absorbed, but oil could not be taken up, and was rejected by the 

 nostrils. 



Such drugs as morphia, pilocarpine, physostigmine, etc., are all 

 rapidly absorbed from the air passages,* and produce their 

 physiological effect in a shorter time than when simply injected 

 under the skin. The lungs also have the power of absorbing 

 certain poisons such as curare, which are not absorbed when intro- 

 duced into the digestive canal. The absorption of water from 

 the bronchial passages is very rapid. Colin introduced 68 litres 

 (6 quarts) of water per hour into the trachea of a horse ; the 

 animal was destroyed at the end of three and a half hours, and 

 no fluid was found in the bronchi. He also poured into the 

 air passages 568 c.c. (1 pint) of water at a time ; repeating this 

 without intermission, he poured in 42 litres (74 pints) of water 

 before he caused death. So rapid is absorption from the bronchi, 

 that a horse may be placed under chloroform almost instanta- 

 neously by an intratracheal injection of the drug.f The rapidity 

 of absorption is therefore very great, but in spite of the facility 

 with which drugs are taken up, the lining membrane of the 

 bronchial tubes is remarkably tolerant of such irritating agents 

 as turpentine, strong liquid ammonia, acetic acid, etc., and 

 offers in a state of health an almost impassable barrier to 



* It is interesting to observe that the injection of liquids into the trachea 

 (either high up, or as low as its bifurcation) excites the reflex act of swallow- 

 ing, probably due to stimulation of the sensory fibres of the inferior laryn- 

 geal nerve. 



| It is not intended here to recommend the intratracheal administra- 

 tion of chloroform, which is not only dangerous, but produces the greatest 

 excitement in the patient. 



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