1913] Walter Lewis Croll 5^5 



Results obtained with the original Meigs method. While 

 the results first obtained by this process seemed to compare very 

 favorably with those obtained by the Soxhlet method, a series of 

 investigations was begun to determine whether this was a mere 

 coincidence or due to the efficiency of the method. For this pur- 

 pose there were secured twelve samples of human milk f rom women 

 in various stages of lactation and six of cow milk, from as many 

 dairies so widely separated that in no two cases were the milks from 

 the same herd. In all determinations the milk for both the Meigs 

 and the Soxhlet methods was taken from one specimen, and at the 

 same time, so that the samples were as nearly uniform as it was 

 possible to get them. In every weighing the figures were recorded 

 to O.Ol mg, The results are given in the accompanying table. 

 The average difference in the results of the eighteen determinations 

 recorded in the table is 0.0234 per cent. 



The data in the table show that the method is useful for the 

 determination of fat in both cow and human milk, and that it is 

 applicable to all stages of lactation and to all kinds of milk. The 

 degree of accuracy is such that it can be used in practically all work ; 

 the differences between the results obtained by this method and 

 those by the Soxhlet, as may be seen from the individual determina- 

 tions given in the table and from the average difference for the 

 series, are so small that they fall within the limits of experimental 

 error. 



A modification of the Meigs process. In the manipulation, 

 it was found that the use of the pipette was exceedingly tedious, 

 required a great deal of skill and practice, and that, even under the 

 most favorable circumstances, the possibility of error was great. 

 To obviate this danger, we devised a simple inexpensive piece of 

 apparatus (Plate 7). If only ordinary care is exercised in its use, 

 the possibility of error is practically eliminated, This apparatus 

 renders use of the pipette unnecessary, there is no need for careful 

 attention to the protein layer or to the end of the pipette, and the 

 speed of the whole process of removing the ethereal Solution and 

 washing away the last traces of fat is markedly increased. 



