366 Scientific Proceeding h. Royal Dublin Society. 



extracted with ether. After twenty-four hours the pats were removed, and 

 the paper scraped clean of adhering butter, and then extracted with ether in 

 a Soxhlet extractor. (It will be convenient to refer to the process by which 

 the butter passes into the filter-paper as diffusion, though obviously diffusion, 

 capillarity, and viscosity all play a part in it.) 3 grains of a yellowish 

 oily liquid were obtained, which did not solidify when allowed to stand over- 

 night at 15° C, but became solid when placed in a room at 10° C. The 

 solidifying-point was determined by a cooling curve. The extract was heated 

 to 30° C. and placed in a test-tube with a thermometer. The test-tube 

 was separated by an air-space from a boiling tube to ensure more regular 

 cooling. The latter was immersed in a bath containing melting ice constantly 

 stirred. Solidification, or more precisely the clouding of the liquid, began 

 at the bottom at 12° C. and was completed at 10° C. The cooling curve gave 

 a well-marked stationary temperature at 102° C, indicating that the extract 

 consists mainly of a single fat or a group of fats having this solidifying- 

 point. A mixture such as butter gives no stationary temperature. The quantity 

 of the extract was too small to make any complete examination by chemical 

 methods. Its iodine value was found to be 41 grams per 100 grams of fat. 

 From this it may be concluded that this extract contains oleic acid in much 

 the same proportion as the original butter. E'or comj^arison it may be remarked 

 that a mixed triglyceiide such as butyro-palmito-olein would give an iodine 

 value of 38 and butyrodiolein of 73. 



A more systematic investigation was then instituted. Comparison of the 

 diffusion of butter with that of butter-fat showed only a slight difference. The 

 water and the texture of the butter have, therefore, very little influence. As 

 it is desirable to obtain the constituents of butter as far as possible unchanged 

 by subsequent heat-treatment, butter was used throughout these experiments. 

 The diffusion was carried out on Whatman No. 1 filter-papers 15 cm. in 

 diameter, which had previously been extracted with ether. On each filter- 

 paper were placed 15 grams of butter in eighteen small cylinders 1 em. in 

 diameter and about 1 cm. high. After varying intervals these butter cylinders 

 were removed, and the paper scraped and extracted with ether in a Soxhlet 

 apparatus. 



One set of observations was carried out at a temperature of 20°-21° C. 

 which was available in the germinating chamber of the Seed Testing Division of 

 the Department of Agriculture. At this temperature the Ijutter became very soft, 

 and dift'usion took place rapidly. An exliaustive experiment to determine ,the 

 approximate quantity of oil in the butter could, therefore, be carried out in 

 a reasonable time. 75 grams of butter in ninety small cylinders were placed 

 on five sheets of filter-paper, and allowed to remain in the germinating 

 chamber for twenty- four hours. 4 grams of extract were obtained. The 

 residue again placed on fi-esh filter-papers for twenty-four hours gave 3 grams of 

 extract. Eepetition of the process gave 2 grams. The time was then extended 

 to forty-eight hours, and for the fifth, and sixth extract to seventy-two hours, 

 and later to ninety-six hours and one hundred and twenty hours. The increased 

 time was necessary to obtain a workable extract. 20 grams of extract, represent- 

 ing nearly 30 per cent, of the original quantity of butter, were obtained 

 in the course of three weeks. The solidification of this series of extracts, 

 or rather the attainment of a solid-like rigidity with its accompanying opaque- 

 ness, took place between 11° and 12° C. The cooling curve gave no stationary 

 temperature. On standing at 15° C, these samples solidified into a gel-like 

 condition, and the colouring' matter present became bleached. A progressive 

 change was shown in the iodine values. The following values were obtained : — 



