4 BULLETIN 855, U. S. DEPARTMENT OF AGRICULTURE. 
ent in use. It may be easier, in fact, because the presence of rosin 
hastens the saponification of the oil. • - 
The mean combining weight of rosin was taken as 346. * 
Saponification value of 1 gram of linseed oil in terms of sodium 
hydroxid equals 0.137 gram. 
28X0.137= 3.83 grams sodium hydroxid needed to saponify 28 
grams oil. 
3.83 X — - = 33.13 grams rosin equivalent to 28 grams oil. 
33.13 X z /i =24.82 per cent rosin (approximately 25 per cent). 
This rosin-soy-bean-oil-cresol solution remains a homogeneous liquid 
when cooled to 32° F. It is readily soluble in distilled water. The 
freshly prepared 3 per cent solution is clear and remains clear for 
more than 1 hour. The rosin-linseed-oil-cresol solution, rosin-oleic- 
acid-cresol solution, rosin-fish-oil-cresol solution containing 25 parts 
by weight of rosin and 7 parts by weight of oil or equivalent in fatty 
acid have these properties also. 
COST OF MATERIALS USED 2 
Sodium hydroxid, 76 per cent, 4 pounds, at $3.25 per 100 pounds $0. 13 
Cresylic acid, 95 per cent, 53 pounds, at $0.77 per gallon 4. 74 
Linseed oil, 28 pounds, at $2.20 per gallon 8. 00 
Soy-bean oil, 28 pounds at $0.20 a pound 5.60 
Rosin, 25 pounds, at $17.50 per 280 pounds 1. 56 
Soy-bean oil, 7 pounds 1.40 
Cost of 100 pounds of saponified cresol solution made with — 
Linseed oil, 28 per cent 12. 87 
Soy-bean oil, 28 per cent 10. 47 
Rosin, 25 per cent, soy-bean oil, 7 per cent 7. 83 
Saponified cresol solution made with linseed oil (28 per cent) costs 
64.5 per cent more than that made with rosin (25 per cent) soy-bean 
oil (7 per cent). Saponified cresol solution made with soy-bean oil 
(28 per cent) costs 33.7 per cent more than that made with rosin 
(25 per cent), soy-bean oil (7 per cent). Saponified cresol solution 
made with oleic acid, fish oil (menhaden), or soy-bean oil fatty acids, 
would cost more than the rosin (25 per cent), soy-bean oil (7 per cent). 
Bacteriological tests, 3 using a modified Bideal-Walker method, 
were made of saponified cresol solutions containing cresol (50 per 
cent) and different soaps equivalent to 28 per cent linseed oil. No. 
10 was made with rosin soap; No. 11, linseed-oil soap; No. 12, soy- 
bean-oil soap; No. 13, fish-oil soap; No. 14, rosin soap f, soy-bean-oil 
1 See Lewkowitsch, Chemical technology and analysis of oils, fats and waxes, ed. 5, vol. 1, p. 346, and 
Bureau of Standards Circular 62, p. 6. 
2 Oil, Paint and Drug Reporter, July 21, 1919. 
3 These tests were conducted by Dr. F. W. Tilley, of the Bureau of Animal Industry. The modification 
consisted in the use of an unadjusted culture medium prepared as recommended by the committee of the 
A. P. H. A., on standard methods of examining disinfectants, in the American Journal of Public Health, 
July, 1918. 
