I9I2] Jacoh Rosenbloom 65 



do not permit the diffuslon of lecithans under the conditions of the 

 tests to be described, and they were preferred for this work for that 

 reason. The cause of the observed difference in permeability is 

 unknown to us, but will soon be made the subject of special inquiry. 

 The substances to be tested in the diffusion experiments were dis- 

 solved in 100 to 200 c.c. of ether (anhydrous and distilled over 

 sodium), the concentrations of the Solutions varying from 0.5 to 

 5 per cent, The Solution or Suspension was carefully poured 

 through a funnel into a new air-tight rubber condom in such a way 

 as to preclude the possibility of overflow upon the external surface. 

 The bag was then immersed in from 100 to 200 c.c. of pure ether in 

 a wide-mouthed bottle of convenient size, and suspended loosely by 

 a thin cord held securely between the stopper and neck of the 

 tightly stoppered bottle. The bottle was kept well stoppered 

 throughout the whole of each test to prevent egress of ether and 

 ingress of dust and other extraneous matter. 



1. Ether extract of egg yolk. Within five minutes after ether 

 extract of egg yolk is subjected to the diffusion treatment described 

 above, the lipochrome appears in the dialysate, diffusion currents 

 being visible about the same time. The following substances can be 

 detected in the dialysate after short periods of dialysis: fat, fatty 

 acid, cholesterol, and lipochrome. The lecithans do not pass 

 through the Condoms, even during prolonged periods of dialysis. 



We tested for lecithans in the dialysate by analyzing the evapora- 

 tion residue for phosphorus by the fusion and Neumann methods. 

 and by seeking an " acetone precipitate " in the concentrated ether 

 Solution after the addition of electrolyte (sodium chlorid). Some- 

 times a positive phosphorus test was obtained from a dialysate 

 which did not yield an " acetone precipitate." In such cases, it was 

 found that this result was due to the presence of glycerophosphoric 

 acid in the dialysate. If to a Solution of lecithans, which, after 

 dialysis in a condom, does not yield a phosphorus Compound to the 

 dialysate, one adds some glycerophosphoric acid, and then dialyzes 

 this Solution through the same rubber condom, glycerophosphoric 

 acid appears in the diffusate. 



2. Ether extract of brain. The dialysate from ether extracts 

 of brain contained fat, fatty acid, and cholesterol. Lecithans failed 

 to dialyze. 



