Scientific Proceedings. 



133 



ments we failed to secure sufficient quantities of lymph from the 

 gland for the freezing point determination. Since we have only 

 five experiments on which to base our deductions, we do not con- 

 sider the above statements final ; but the fact that the lymph 

 obtained from the active gland had in three cases considerably 

 lower osmotic pressure than the serum, apparently eliminates 

 osmosis as the factor effecting the transfer of water from the blood 

 capillaries in the active gland. That leaves the secretory nerve 

 theory and the " hormone " theory, as before stated, the only occu- 

 pants of the field. The latter seems to us the most probable one, 

 and our work is now directed towards proving or disproving it. 



6. The osmotic pressure of the lymph from the neck lymphat- 

 ics of the horse, collected with the animal under chloroform anes- 

 thesia, may be of slightly higher, of the same or of considerably 

 lower osmotic pressure than the serum. Hamburger states that the 

 osmotic pressure of the lymph collected from the neck lymphatic 

 of the horse is thirteen per cent, higher than that of the serum. 

 Hamburger collected the lymph from animals not under anesthesia. 



We ourselves have had two cases which showed that the 

 osmotic pressure of the neck lymph was more than one atmosphere 

 lower than that of the serum. Here we are face to face with the 

 old problem of secretion of urine, only here the relation is re- 

 versed. Even assuming that the capillary pressure in the head 

 and neck region of the horse is 100 mm. Hg., this would not avail 

 to overcome the difference in osmotic pressure of the lymph and 

 the serum in these two cases, so that filtration could be the factor 

 in the lymph production. Unless the lymph in these two cases 

 was rendered dilute by the absorption by the tissue cells of the 

 constituents making up the osmotic pressure, which although 

 improbable is now being investigated, we have here a demonstra- 

 tion of a formation of lymph by a secretory activity of the capillary 

 walls. 



7. The osmotic pressure of the lymph from the neck lymphat- 

 ics of the dog is usually lower than that of the serum. It is rarely 

 greater. Leathes states that the thoracic lymph of the dog is 

 always of higher osmotic pressure than the serum. In two of our 

 experiments we collected lymph also from the thoracic duct, find- 

 ing it in both cases of higher osmotic pressure than the neck 



