THE FORMATION OF LYMPH. 411 



not found to increase the flow of lymph in any marked 

 degree (Paschutin, 1 Emminghaus, 2 Rogowicz 3 ). 



In other researches curare was found to have a specific 

 influence in increasing the lymph flow (Paschutin, Rogo- 

 wicz), and in others stimulation of certain nerves was found 

 to have a similar effect (Ostroumoff). These difficulties 

 were differently interpreted by different physiologists, and 

 although such expressions as "changes in the. capillary 

 walls," "an active property in the cells of the capillaries," 

 etc., do occur, there was nothing positive. They, however, 

 paved the way to Heidenhain's work, 4 and to the considera- 

 tion of his paper we can now pass. 



Almost all previous experiments had been made on the 

 lymph of the extremities, but Heidenhain performed his 

 researches by observing the amount of lymph coming from 

 the thoracic duct in fasting dogs. A cannula was placed in 

 the thoracic duct, by means of which the lymph was 

 collected. The first series of experiments were those in 

 which mechanical interferences with the circulation were 

 brought about. The aorta was plugged by means of an 

 elastic ball introduced through the right carotid artery. On 

 the mechanical theory one would expect the outflow of 

 lymph to cease or nearly so with the fall of blood pressure 

 that was the result of this procedure. But though the 

 pressure as measured in the crural artery fell nearly to zero, 

 the lymph was found to go on flowing for one or two hours. 

 In the next set of experiments the portal vein was ligatured 

 near the liver ; this led to a great hyperemia of the 

 abdominal organs ; while the arterial pressure fell from 100 

 to So mm. of mercury, the quantity of lymph increased about 

 fourfold, and the percentage of proteids in it fell from 6*5 

 to 4*4 per cent. Simultaneous occlusion of both portal vein 

 and aorta still produced an increased lymph flow. In the 

 third set of experiments the vessel occluded was the 

 inferior vena cava above the diaphragm ; the results of this 

 were that the intestines became anaemic, the liver and 



1 ludwigs Arbeiten, 1873, p. 95. % Ibid., p. 396. 



3 Pfliigers Archiv, xxxvi., p. 252. * Ibid., xlix., 1891. 



