viii NOTE 



He travelled much, having visited nearly all the 

 European capitals, besides travelling a great deal in 

 America, and thus by means of his extensive and acute 

 observation added greatly to his scientific and general 

 knowledge. He was a man of splendid physique and of 

 profound intellect, and satisfied his own mind on all topics 

 in which he was interested. He was for long engaged in 

 the work now presented, and it was his intention to see 

 it through the press ; but unfortunately he was overtaken 

 by a fatal illness, and in consequence this duty fell into 

 other hands. He died at Harrogate in September, 1907, 

 at the age of sixty-nine years. He was unmarried. 



His MS. passed into the hands of his trustees, Alex- 

 ander Gemmell, banker, Bradford, and Dr. Quintin 

 M'Lennan, Glasgow, and but for the prolonged illness of 

 the latter, the work would have been issued long ago. 

 After a great deal of care, work, and anxiety on the part 

 of his trustees it has now been completed. 



Dr. M'Lennan, who has had a deep interest in it all 

 along, and knew Dr. Logan's views with regard to it, had 

 the great satisfaction and good fortune of having his 

 friend, Dr. P. Henderson Aitken, of Oxford, as co-editor. 

 They have done their part of the work to the best of their 

 ability, and in accordance with Dr. Logan's strict wishes 

 and instructions. No alterations or excisions of any of 

 the text were permitted, and his wishes in that respect 

 have been rigidly observed. Here the trustees' responsi- 

 bility ceases, and the work is now put into the hands of 

 the medical profession by them, in the hope that it will be 

 cordially received. 



The Editors have to express their indebtedness to 

 Messrs. Longmans, Green & Co., Messrs. Macmillan & 

 Co. Ltd., and the Clarendon Press, Oxford, for assistance 

 by the loan of illustrations which the author had selected 

 for this work. 



