OF ABSORPTION. 



41 



be in support of his purely physical properties ; but, although the vital properties arc 

 chiefly predominant in the operation, yet those for which they contend may have still 

 a place to a certain extent, which extent is modifiexl by a superior influence. 



Investigations into the process of absorption have also been entered upon in America. 

 Doctors Lawrance, Coates, and others, made thirty-four experiments in which the prus- 

 siate of potass was introduced into the alimentary canal : from these it appears that ar- 

 ticles taken into the stomach may be conveyed into the circulation by three channels ; 

 namely, the vena portae, the oesophageal veins and the thoracic duct, and if all these 

 are closed, the absorbed matters are no longer conveyed to the circulation or to the^ 

 urine. With regard to the quantity conveyed b\ each, they had no accurate means of 

 judging. As the quantity of fluid, however, contained in the vena portarum, is so much 

 greater than in the thoracic duct, it follows, that to produce a colour of equal in- 

 tensity, a much larger amount of the colouring matter is requisite, and, as the serum ot 

 the blood of the vena port gave an equally deep colour, the greater proportion of the 

 materials must have been absorbed through the veins contributing to this system of 

 vessels. 



In consequence of reading the experiments of professor Mayer of Gottingen, upon 

 absorption in the lungs, Doctors Lawrance and Coates made a few with that reference. 



The animals generally died in about a minute after the injection, from suffocation, 

 by the ligatures which they placed on the tracheas of most of them. These experiments, 

 \ve think, go to favour the ideathat absorption from the mucous membrane of the lungs, 

 is performed principally by the pulmonary veins. They lay particular stress upon ex- 

 periments 5th and 6th. In the first, the blood from the left side of the heart indicated 

 the agent in much larger proportion than that from the right side, both being examined 

 about the same time : viz. seven minutes. In the second, where the examination was 

 made in a much shorter period, viz. three minutes and a half, and four minutes and a 

 half, the article was distinctly found in the left side of the heart before it had arrived 

 in any other part of the system. 



The effect of infiltration was also remarkable in these experiments. 



The results of five trials of the prussiate in the cavity of the abdomen are here arranged 

 for inspection. 



The short time in which the prussiate reached the upper part of the thoracic duct in 

 the above cases, induced them to make four other trials in order to ascertain the earli- 

 est period at which that took place. Half an ounce of solution was employed in each 

 case. 



In the first animal, a kitten, the salt first arrived at the spot of observation in four 

 minutes, and the quantity gradually increased till seven or eight minutes. In the 

 second kitten, it appeared in two minutes, The serum of this animal gave a blue 

 tinge. In the third kitten, in three minutes and a half. Serum of blood also blue. In 

 the cat, it first appeared in thirteen minutes. 



In these cases, the thoracic duct was cut off near its insertion ; and the test applied 



F 



