366 
modifications is retained by the glomerular membrane, and the other 
is aliowed to pass through. 
As appears from tables | and II, of not too strong concentrations 
about the half is retained. 
It is now, upon closer inspection of what has been handled above, 
possible to calculate in a simple way the relative quantities of a- and 
B-galactose. 
If we call the amount of the « variety (rotation + 135°) in the 
galactose solution, in which there is equilibrium between « and 8, x, 
then 1-—x is the amount of the 8 variety (rotation + 53°), and then, 
because the rotation of the mixture 81° is, the following equation 
must hold: 
135x + 53 (1—x) = 81. 
x= Ojo: 
1—x = 0,66. 
Therefore the ratio between the quantities of the « and > forms 
is 34 : 66. 
These figures cannot boast of great accuracy, because, in the first 
place, we find with other writers for the specifie rotation of the « 
variety a value of 117° and not 135°. If this value is the true one 
then we should get a ratio of 44:56 between the modifications. 
Further it must be remembered that the concentration and temperature 
of the galactose solution are not without influence on the equilibrium. 
In general however it can well be said that the greater half is the 
3-form (y-form of Tanrwrt). 
A similar proportion can also be deduced from the researches of 
KE. Roux in connection with the rate of conversion of the « into 
the y-form. , 
It is now very remarkable also in our perfusion experiments that 
more or less the half of the galactose is retained. This parallellism 
ean be considered as supporting our hypothesis. Whether it is the 
«- or y-form which is retained we cannot venture to say with any 
certainty at present. That might be the case, if, in the first place, 
the values of the rotations which we used above in deducing the 
relative quantities of the «- and g-forms had been taken at the same 
concentrations as the physiological concentrations (0.05°/,—0.15°/,), 
which we used in our perfusion experiments. 
In the second place the values found along chemical lines for the 
rotation, in concentrations of 6°/,—18°/,, leave much to be desired. 
And then in the next place it must not be forgotten that, as a matter 
of course, the degree of accuracy of our determinations of the 
