— 149 — 



taining a little sulphuric acid, into which this tube just dips ; when 

 as many tubes as are to be charged are thus arranged in place and 

 the hydrogen is turned on, the even flow of the current through 

 the whole number is secured by raising or lowering, a very little, 

 the several tubes through which the outflow passes, so as to get a 

 little more back pressure for one, or a little less for another, as 

 may be found necessary. When the drying is supposed to be com- 

 pleted, the tubes are weighed again with their close stoppers, and 

 so on. * 



Then, for the extraction of the fat, the unstoppered tube with 

 contents is put directly into a Soxhlet extractor, or into a continu- 

 ous extractor, for the treatment with ether, in the usual manner. 

 Fig. 4 is a representation of the form of a continuous extractor 

 which has been used in my laboratory for many years with perfect 

 success ; it was described in the second annual report of the Cor- 

 nell University Experiment Station, 18S2-3 ; as slightly modified, 

 it is reproduced here simply in order to make the set of apparatus 

 complete for the work in hand. The bottom of the inner tube is 

 perforated at h to allow the ether that has entered through the lat- 

 eral openings k k and passed through the substance to flow back 

 into -the flask connected with the tube^. By the bending to one 

 side of this tube, the droplets of ether that may be projected up- 

 wards in the boiling are less likely to come in contact with the 

 cork, a matter of some little consequence when the liquid becomes 

 pretty well saturated with fat. 



When the extraction is completed there seems to be no reason 

 why the amount extracted cannot be determined by weighing the 

 dried contents of the tube, as well as by weighing the substance 

 extracted ; and the drying in hydrogen is much more easily man- 

 aged in the former case than in the latter ; but I have not yet had 

 time to test this variation of the method. 



The ether-extract being estimated, it is evident that the contents 

 of the tube, now in the proper condition for the determination of 

 the fibre, can be transferred without any difficulty to the digestion 

 flask, with the aid of a wash-bottle containing the required quan- 

 tity of boiling sulphuric acid ; that the platinum disk and small 

 quantity of asbestos must accompany the substance of course does 

 no harm. 



It now remains to be demonstrated that this apparatus serves its 

 intended purpose. The following observations made by the assist- 



