310 Chittenden and Whitehouse—Metallic 
amount of copper salt to obtain any separation of the albuminate. 
As a result, the filtrate contains considerable albumin and copper, but 
even after several hours washing on the pump (the filtration is slow — 
at the best) the precipitate still gives up traces of albumin, as shown 
by acetic acid and potassium ferrocyanide, long after all traces of 
copper have disappeared. It is not impossible to wash the compound 
and reach a point where the wash-water contains neither copper nor 
albumin, but when the washing goes on slowly and the water remains 
more or less in contact with the albuminate for 24 hours, then fre- . 
quently the washings will show traces of albumin continuously, with- 
out our being able to reach a point where the test fails to give any 
reaction whatever, or to show any special change in the intensity of 
the reaction. EL 
The following series of experiments would appear to substantiate 
this view. The first six were washed‘for about twelve hours, when 
no copper reaction could be obtained in the washings and only the 
slightest reaction for albumin. The last six were washed for sixteen 
hours, and finally stood over night on wet filters with more or less 
water on them. At the end of this time, the washings continued to 
show a reaction for albumin with acetic acid and potassium ferro- - 
cyanide, and indeed the reaction appeared to increase rather than . 
diminish in intensity on further washing. The washings contained 
no copper. 
Following are the results of the analyses : 
Series IX.— With CuSO, 
No. Amt. sub. taken. Wt. CuO. Per cent. Cu. 
1 0-4207 gram. 0:0052 gram. | 0-99 
2 0:4676 0:0058 0:98 
3 0:4881 0:0062 1:00 
4 0°3162 0:0087 0°91 
5 0°2882 0: 0032 0:89 
6 0°1857 0:0024 1:02 
7 0:2892 0:0050 1°34 
8 0°4137 0:0060 ais} 
9 0°4077 0:0060 1,18 
With Cu(C,H,0,),- 
10 06067 0°0126 1°64 
11 06889 0°0111 1°27 
12 0°7126 00109 1°22 
