SOME FURTHER NOTES ON THE HYDROLYSIS OF STARCH GRAINS UNDER POLARIZED LIGHT

The interest taken by workers in America in the effects of radiation of all kinds and in particular of polarized light, together with the confirmation of my results, kindly expressed by Prof. MACHT and Mr. MORRISON, lead me to hope that some fuller account of these experiments may be acceptable. The first paper published in Dec., 1924,1 was necessarily of a preliminary character, but recent work has completely confirmed these early results and has made the whole process much clearer. Like all new ideas, this work has not escaped criticism,2 to which a reply3 has been given, and it is hoped that the following added notes and photographs will show that the views put forward by our critics are quite untenable. 1. As stated in the above mentioned paper, washed and centrifuged starch grains were suspended in water, to which weak diastase was added and a few drops of the starch suspension were mounted on a microscope slide placed over a Nicol prism. Two controls were always arranged, one in ordinary light, and the other in darkness. It has been suggested that the whole effect was due to pressure of the cover slip, but this factor would have affected the controls also. 2. In the second place, it is most important to note that the whole process was watched carefully under the microscope for four or five hours, the changes were noted and drawings were made. Unless this is done, a superficial observer may easily miss the results, particularly if no cover slip is used, as the grains on hydrolysis become lighter, exude their contents, and the empty coats float to the edge of the slide or vessel. 3. The experiment was repeated nearly twenty times, and the result was shown to nine or ten different observers, chiefly professors and lecturers of the University of London.