Page:Defensive Ferments of the Animal Organism (3rd edition).djvu/236

 products of decomposition, contained in it, have a toxic effect.

To determine the range of rotation, a perfect instrument is necessary. The polarizing apparatus of Schmid and Hänsch, of Berlin, is one that answers

. 10.

(a) Ocular for taking readings; (b) polarization tube; (c) sodium flame; (d) for illumination; (e) battery.

all the requirements (fig. 10). It allows of readings to the hundredth part of a degree. Since everyone makes individual errors in taking readings, i.e., the range of rotation of the same solution is