198 INFLUENCE OF BILE AND BILE SALTS 



methods. 1. Using Kiihne's well known method,* the fresh 

 pancreatic glands of oxen were freed from fat and thoroughly 

 dehydrated by long soaking in a large volume of strong 

 alcohol and lastly in ether. To prepare the extract, 20 grams 

 of the dry tissue were warmed at 40 C. for 24 hours with 

 200 c.c. of 0.1 per cent salicylic acid, the solution strained off, 

 filtered through paper, made exactly neutral with sodium car- 

 bonate, and diluted with water to 1 litre. The sodium 

 salicylate formed on neutralization will serve to prevent 

 putrefaction for short periods, while the addition of a little 

 thymol will preserve the fluid indefinitely. 2. Using Roberta's 

 method,f pancreatic glands from pigs, freed from fat, were 

 ground up with broken glass and soaked in four times their 

 weight of 20 per cent alcohol for 4-5 days with frequent 

 agitation. The extract was then filtered through paper, 

 yielding a clear, slightly yellow fluid of strong proteolytic 

 power. 



The proteid material used in measuring the relative proteo- 

 lytic power of the mixtures was purified blood fibrin, pre- 

 pared by soaking carefully selected, well-washed fibrin in cold 

 and boiling water until all soluble matter was removed, after 

 which the fibrin was thoroughly extracted with cold and boil- 

 ing alcohol and lastly with ether. The friable mass was then 

 ground to a coarse powder and the latter passed through a 

 series of sieves so as to bring together particles of the same 

 size. It was then dried at 110 C. until of constant weight, 

 and preserved for use. In some few experiments coagulated 

 egg-albumin was made use of, in which case the actual content 

 of dry proteid was determined by drying a given weight of 

 the coagulum at 110 C. and then deternuning the ash by 

 ignition. 



The character of the bile employed is specified in each 

 experiment The secretion was always obtained as fresh as 



* Kiihne, Untersuchungen aus d. physiol. Institute, Heidelberg, 1878, I, 

 p. 223. 



t Roberts, On the Digestive Ferments, etc., The Lumleian Lectures, 

 London, 1880. 



