Page:Defensive Ferments of the Animal Organism (3rd edition).djvu/98

 however, in this experiment we use the blood plasma, or serum, of a dog to which cane sugar has been administered as an injection, either subcutaneously or directly into the circulation. then, on bringing this plasma and cane sugar together. we observe that the reducing potentialities of the mixture are considerably increased. Simultaneously, it is possible to show that the quantity of the admixed cane sugar diminishes.

These experiments give very positive results when the splitting action of the plasma is investigated with the aid of the optical method. in this case plasma is taken from a normal dog in a certain quantity, and a known amount of cane sugar solution is added: a polarization tube is ﬁlled with the mixture, and the rotation of the latter is ascertained. The readings of the polariscope are taken from time to time, and the tube is kept during the intervals in an incubator at 37° C. It is found that the initial rotation keeps constant.

Now. if an injection of cane sugar is made into the circulation of the same dog from which the plasma was taken. it may be demonstrated after a very short time that its plasma is now capable of breaking up cane sugar. The strong rotation to the right, which we observe at ﬁrst. decreases continuously. It approaches zero, and ﬁnally, passing zero, it travels to the left. We obtain eventually a left-handed