Thrombosis in Phlebitis. 



37 



ficially lengthened by daily dosage of 2 gms. of citric acid and one 

 third used as control animals. The drugs were introduced into 

 the stomach by tube feeding and it was found possible, with this 

 dosage to reduce the coagulation time of the blood in the calcium 

 lactate animals one half and to lengthen it in the citric acid animals 

 about one third. Corroborating work already well authenticated, 

 the maximum effect of these drugs takes place about two hours 

 after their administration, and probably entirely passes away within 

 twelve hours, especially with the rapidly excreted calcium salts. 

 In our animals the drugs were continued in daily doses through- 

 out the experiment, since it was found that effects were quite as 

 apt to occur several days after the initial injury as immediately on 

 its infliction, thus more closely approximating the conditions as they 

 occur in man. 



When autopsies were to be performed the animals were chloro- 

 formed and while the heart action was still vigorous a carotid 

 artery was opened and the animal suspended so that the blood was 

 very generally emptied from all the vessels of the body, and post- 

 mortem clot or fibrin could not become confused with the true 

 thrombi. We believe this to be an important step in the technic. 



Our experiments may be grouped in two series : Series I com- 

 prises local injuries produced in and around the ear veins. Nine 

 experiments of this character were performed. Series II includes 

 attempts to produce vascular lesions predisposing to phlebitis and 

 thrombosis by intravenous injections of various irritants. Five sets 

 of experiments. 



Series I ; Experiment a. — A segment (3 cm.) of the dis- 

 tended marginal vein was isolated by compression between two 

 artery clamps and the intervening vein distended with blood was 

 intermittently compressed with toothed forceps for five minutes 

 when minute hemorrhagic extravasations along the course of the 

 trunk were demonstrable. The isolating clamps were then removed 

 and the circulation allowed to become reestablished. The result- 

 ing perivenous inflammation was slight and no thrombosis followed 

 either in the calcium citric acid or control animals. 



Experiment b. — Clamping the marginal vein with ordinary 

 paper clips, cutting off at the time the anastomosing circulation, 

 for thirty minutes, was followed by immediate reestablishment of 

 the normal blood flow in all animals without subsequent results. 



