I9I2] 



William H. Welker 



n 



TABLE 2 



Results of experiments with bags of parchment paper 



FOURTEENTH SeRIES. 



III. ON THE UTILITY OF COLLODION.BAGS IN EXPERIMENTS OF 

 THE KIND DESCRIBED IN THE FOREGOING SECTIONS 



Experiments like those in the sixteenth series (Table 2) were 

 attempted with bags made of collodion, but in each case the bags 

 were perforated and in part dissolved, by the Contents, before the 

 experiment could be fairly started. 



Several years ago, Dr. Gies observed, in some dialysis experi- 

 ments with collodion membranes, that ethyl ether could be kept on 

 the aqueous Contents of collodion bags, for preservative purposes in 

 such tests, without inducing distintegration of the bags. In repeti- 

 tions of the experiments a year or two later, however, it was found 

 that ether under such circumstances often caused deterioration of 



*The results in this series, while apparently negative in each case, were 

 somewhat doubtful owing to the fact that the paper contained some soluble 

 material, which rendered the biuret test more or less uncertain. See the results 

 of the tests in the sixteenth series. 



*The parchment paper was washed free from soluble matter before the 

 beginning of the tests. 



