I9I3] Alfred P. Lothrop 549 



cipitated from the extract a product which gave additional histon 

 tests, proving the presence of histon in the Compound. 



An interesting confirmation of these results was obtained by 

 repeating the preparation with histon precipitated with sodium 

 Chlorid from a hydrochloric acid extract of tom-cod milts (see pre- 

 ceding abstract) . This product resembled, qualitatively, the thymus- 

 histon salt but was not precipitated from the sodium carbonate sol. 

 by hydrochloric acid. It was precipitated readily with nitric acid 

 and this precipitate yielded histon on extraction with 0.8 per cent. 

 hydrochloric acid sol. 



95. Further experiments on the preparation of modified col- 

 lodion membranes for use in dialysis experiments. Frank R. 

 Elder. In continuance of the studies, in this laboratory, of col- 

 lodion membranes/^ we have endeavored to determine the compara- 

 tive permeabilities of collodion-fat combinations. The tests were 

 conducted with aqueous Solutions in small bags made by Dr. Gies' 

 method, as recently published by Clark/ ^ from mixtures of U. S. P. 

 collodion sol. and pure olive oil. Uniform mixtures of i part of 

 olive oil and 3 parts of collodion sol. did not yield bags strong 

 enough for the use intended, but satisfactory membranes could be 

 obtained from mixtures containing i part of oil and 4 of collodion 

 sol. Bags made from mixtures of i part of olive oil and 9 of col- 

 lodion sol. were impermeable to chlorid, sucrose and peptone in 

 dialysis experiments of a week's duration. Bags made from mix- 

 tures of I part of oil and 99 of collodion sol. were occasionally im- 

 permeable to each of these substances, though such bags frequently 

 permitted all of them to dialyze freely when associated pigment 

 was unable to diffuse. It is our Intention to determine, if possible, 

 whether such diffusion differences depend upon inequalities in the 

 distribution of oil in the bags, " age " of the membranes, etc. 



96. Comparative studies of the permeability of collodion and 

 collodion-fat membranes. Samuel Gitlow. Bags were prepared 

 as usual (see the preceding abstract), and the tests were conducted 

 in water. The following water-soluble dyes diffuse through piain 

 collodion membranes used immediately after removal from the 



12 Gies: Proc. Amer. Soc. Biol. Chem., 1912, ii, p. 75; Journ. Biol. Chent., 

 1912, xi, p. xli; Science, 1912, xxxv, p. 396. 



13 Clark: Biochemical Bulletin, 1912, i, p. 198. 



