LYMPH FORMATION 591 



glands are rendered non-toxic before passing into the general 

 circulation. 



The experimental evidence brought forward by Asher to show 

 the toxicity of lymph consisted in injecting into the carotid artery 

 of a dog 20 c.c. of its own defibrinated lymph derived from the 

 cervical lymph trunk. He observed alterations in the blood 

 pressure curve and in the respiratory and cardiac rhythms, which 

 were absent when similar quantities of normal salt solution or of 

 the animal's own defibrinated blood were injected. In the cat, 

 Brodie has shown that intravenous injection of the animal's own 

 blood serum or defibrinated hydrocele fluid causes arrest of 

 respiration, inhibition of the heart, and general vaso-dilatation ; 

 that the active substance is a proteid, produced when the blood 

 clots and connected with the presence of blood-corpuscles. He 

 was unable to obtain similar typical effects in dogs. Considering 

 the smallness of the effects observed by Asher, it may well be 

 doubted whether they were due to poisonous substances produced 

 by tissue metabolism, and not to substances liberated into the 

 lymph during defibrination. Asher has not shown that lymph after 

 leaving lymph glands is less toxic than before it has reached them. 



Asher' s most important experiments in proof of the proposition 

 that increased lymph flow always accompanies increased cell 

 activity are the following : 



(1) Activity of the salivary glands brought about reflexly from 

 the mouth increases the flow along the cervical lymph trunk. 

 But if the glandular activity is prevented by atropin, then, as 

 Cohnheim showed, stimulation of the chorda tympani leads to no 

 increase in lymph flow in spite of the vaso-dilatation. Bainbridge 

 has confirmed this result. 



(2) Intravenous injections of bile or the liberation of haemoglobin 

 within the circulation are known to increase the activity of the 

 liver. Correspondingly they increase the flow of a more con- 

 centrated lymph along the thoracic duct. Bainbridge has con- 

 firmed these results, using isotonic solutions of sodium taurocholate 

 and haemoglobin. He has further shown that the pressures in the 

 aorta, inferior vena cava, and portal vein are unaltered ; that the 

 lymph does come from the liver, but is not so concentrated as that 

 obtained by injection of peptone ; and that the results of their 

 injection and their mode of action is different from either class of 

 Heidenhain's lymphagogues. 



