VIU INTRODUCTION 



Thus without special aim to be consistent we have taken 

 up the various problems presented by recent workers, feeling 

 generally that it is our duty to record established custom 

 rather than to initiate or to follow hastily each proposed 

 change. 



Thanks are due to several of our North American co- 

 workers for advice and assistance. We would mention especi- 

 ally Dr. Emmett Reid Dunn, Dr. Alexander G. Ruthven, and 

 Mr. Karl P. Schmidt. 



T. B. 



