APBIL 17, 1908] 



SCIENCE 



611 



In bringing my remarks to a close I hope 

 that their main intent, despite their ram- 

 bling and somewhat desultory character, 

 may have become plain to you. I have 

 tried to show you that medical laboratories 

 such as these are indispensable in medical 

 schools which are at all worthy of being 

 known as the medical departments of true 

 universities, and I have maintained that 

 only in such laboratories can students be 

 properly taught, for they come there into 

 direct personal contact with the objects of 

 study, a requisite if the scientific habit of 

 thought is to be engendered. To them, too, 

 your physicians and your guardians of the 

 community's health may resort for making 

 the special laboratory examinations now 

 necessary for the diagnosis, the cure and 

 the prevention of the ills by which your 

 people are afflicted. And, above aU, open- 

 ing off these halls there are some rooms 

 which will, I trust, become the workshops 

 of mature original investigators and others 

 which will serve as nurseries in which will 

 be cultivated those qualities of mind, heart 

 and hand which make men dissatisfied with 

 knowledge as it is and compel them to try 

 to extend it. 



Untrammeled by the traditions and 

 ultra-conservatism which are holding medi- 

 cine back in the mother country, yet pro- 

 tected by intimate connection with her 

 from the whimsical vagaries, the wildness 

 and the freakishness which might otherwise 

 tend to bring medical science here into dis- 

 repute, Canadians have an opportunity and 

 a privilege in medicine they will not be 

 slow to take advantage of, a duty they are 

 sure manfully to assume. There are many 

 young men and women in this country and 

 this province capable of devotion to an 

 ideal cause, independent of personal gain 

 and glory. It is to the credit of Canadian 

 parents that they instil into their children 

 high and noble aspirations, that they teach 

 them to endure privations cheerfully for 



the sake of things greater than mere phys- 

 ical comforts, and that they cultivate that 

 generosity and elevation of spirit which 

 make unselfish human effort not only pos- 

 sible, but really desirable. The fruits of 

 this training will, I dare prophesy, become 

 evident sooner or later in the activities of 

 these laboratories. In them there will be 

 professors and students who will choose as 

 their life work the pursuit of medical truth 

 and the acquisition of medical knowledge 

 for its own sake; as a result of this en- 

 nobling and worthy occupation human suf- 

 fering will be ameliorated, and, perhaps, 

 some patients suffering from maladies now 

 incurable may be healed. May the high 

 aims and purposes of those who have 

 planned these buildings and made their 

 erection possible be realized! May the 

 good that you hope for be the outcome of 

 work in the laboratories which with suit- 

 able solemnity and earnest purpose you 

 have set apart and consecrated to a special 

 service to-day! 



Lewellys F. Barker 

 The Johns Hopkins Univeesity 



THE AMERICAN ASSOCIATION FOR THE 



ADVANCEMENT OF SCIENCE 



SECTION B— PHYSICS 



II 



A Relation of Mass to Energy: Daniel F. 

 CoMSTOCK, Ph.D. (Read by title.) 

 In the paper of which this is an abstract 

 it is shown that the momentum of any 

 purely electi'ic system having any internal 

 motions and constraints, but possessing on 

 the whole a kind of average symmetry, is 

 given by the expression 



V'-[l+ {v/Y)'-Y 



Here M is the momentum of the system, 

 (v) its velocity as a whole, V the velocity 

 of light and W^ the part of the total elec- 

 tromagnetic energy which is represented 



