880 TRANSACTIONS OF SECTION I, 



by acid or peptic digestion, but not in that prepared by tryptic digestion. I Under- 

 took the following experiments to ascertain if possible whether this peptozyme 

 or any similar bodies could be removed from Witte's peptone by the action of 

 A'arions solvents. 



The following was the method I adopted: 25 grams of Witte's peptone 

 were extracted by means of Soxhlet's apparatus, with about 160 c.c. of ether, 

 chloroform, or commercial benzole, nnder a reflux condenser for about twenty- 

 four hours. The solvent was then distilled oft" to a small bulk and allowed to 

 dry completely at room temperature. The solid residue was dissolved in, or 

 rather extracted with, 09 per cent. NaCl solution, in which it was only 

 sparingly soluble, and the extract was injected into an anaesthetised dog through 

 the femoral vein. 



Contrary to the observations of Nolf, I have found that simple hypodermic 

 injection was inefl'ective. In the case even of unaltered peptone a hypodermic 

 injection of 0-1 gram per kilo, of body weight produced no effect on blood-pres- 

 sure, while the same dose givtn intravenously at once produced the characteristic 

 effect. Control injections were made with unaltered Witte's peptone in doses pf 

 O'l gram per kilo. Not more than one per cent, of Witte's peptone is soluble in 

 boiling ether, benzole, or chloroform ; but up to the present I have not been able 

 to carry out any exact quantitative experiments. Some chemical changes also 

 seem to occur during extraction, as the resulting product is only slightly soluble 

 in water, while the original peptone is completely so. 



Experiment I. — Injection of the benzole extract of 50 grams Witte's peptone 

 (10 kilo, dog) = very slight fall of blood-pressure, while the heart's beats became 

 more frequent and diminished in amplitude. 



Injection of 1 gram of the portion insoluble in benzole produced a great and 

 rapid fall of blood-pressure. 



Experivient IL—TIlq same with chloroform extract. Result, very slight fall 

 of pressure. 



Injection of the chloroform insoluble residue and subsequent control injection 

 of witte's peptone were both negative as regards blood-pressure. A sample of 

 blood remained uncoagulated. 



Experiment III, the same as //. 



Injection of chloroform extract = no fall of pressure, A sample of blood 

 taken immediately after did not coagulate. 



Control with 'Witte's peptone = slight fall of blood-pressure, much less than 

 normal. 



I think that the following inferences may perhaps be drawn from the fore- 

 going experiments : — 



1. That the substance which causes lowering of blood-pressure is not ex- 

 tracted from peptone by benzole, ether, or chloroform. 



2. That a substance which confers immunity from the vaso-dilator effect of 

 peptone injection can be extracted from AVitte's peptone by chloroform, but not 

 by benzole. 



3. That chloroform extracts from peptone a substance which diminishes the 

 coagulability of the blood. 



The amount of these extracts used in the above experiments never amounted 

 to more than O'O gram, this being chiefly due to the difficulty of extracting large 

 amounts in Soxhlet's apparatus. The extraction with ether had also to be aban- 

 doned, as the tap-water was not cold enough to condense ether in the summer 

 sveather. 



Fischer's research bids fair to sort out the tangle of complex bodies grouped 

 together as peptones on a sound chemical basis, and if the different constituents 

 could be obtained of definite and constant composition much would thereby be 

 gained towards determining their molecular structure ; but meanwhile I hope I 

 have shown that something may also be done in the same direction by proceeding 

 on physiological lines. 



