KEPARATORY INFLAMMATION IN ARTERIES. 15 



mainly of epithelioid cells ; it effects the permanent closure of 

 the vessel. He thinks that his preparations clearly demonstrate 

 that in the case of the single ligature the organizing elements 

 of the permanent clot are derived from the tunica intima. In 

 the double ligature, on the contrary, the internal membrane in 

 the portion limited by the two threads becomes modified. The 

 substitution of the temporary b^- the permanent clot is accom- 

 plished more slowl}-, since the coagulated blood must produce 

 mortification of the internal membrane, and later become the 

 irritating agent of the middle and external membrane. 



Following the experiments of Bubnoff, Durante declares that 

 never in the single ligature, when the coloring matter has 

 been simply placed upon the vessel, has he been able to find, in 

 the clot or in the wall of the vessels, cells containing gran- 

 ules of vermilion. The same is true of the double ligature 

 when the inflammation has not yet destroyed the limit be- 

 tween the walls of the vessel and the surrounding tissue. If 

 the vermilion is gently' applied to tlie walls of the vessel, the 

 coloring matter remains for man}' days at the periphery of 

 the artery, and in transverse sections it appears as a line dis- 

 tinct and continuous, at the surface of the adventitia. But 

 when the walls of the vessel become confounded with the 

 neighboring tissues by the progress of inflammation, the ver- 

 milion may be recognized here and there in the midst of the 

 tunics. In the single ligature, if the greatest possible care is 

 taken, it is easy at the end of the twelfth day still to perceive 

 the vermilion limited to the perivascular connective tissue; 

 but after prolonged and somewhat rougli friction, he has been 

 able, at the end of a few hours, to demonstrate on the jugnlar 

 vein of rabbits, exposed and included between two ligatures, 

 tliat there exist in the middle of the clot granules of vermil- 

 ion in a free state. The walls of the A'cin were infiltrated 

 with similar granules. The same mauanivre practised upon 

 the arteries causes the vermilion to reach onlv as far as tlie 



