220 REPORTS OF INVESTIGATIONS AND PROJECTS. 



electromotive forces without the passage of an electric current from the out- 

 side. These photo-electric effects constitute the subject of a further investi- 

 gation which is now in progress at his hand. 



(g) The Mathematical Theory of Luminescence, by Professor Merritt. — 

 This theoretical work which is based upon the experimental results obtained 

 in the course of our experiments, together with such other fragmentary data 

 as were available, have appeared in the form of a paper in the Physical Re- 

 view.* It is intended to make this, in a more elaborated form, the closing 

 chapter of the series of investigations completed under the grant from the 

 Institution. The equations formulated by Professor Merritt express and 

 connect in a systematic way the complex and varied phenomena hitherto 

 obtained. They enable one, for the first time, to predict results and prescribe 

 the conditions under which further experiments are to be performed. 



A final report, in the form of an extended memoir covering the ground of 

 these investigations and of those which have been mentioned in earlier reports 

 of progress, will be submitted as soon as the voluminous material in hand 

 can be prepared for publication. The work thus far accomplished, although 

 it has taken the time of several observers for a number of years, is to be re- 

 garded only as a preliminary survey. In this important field of optics very 

 few quantitative measurements had been made up to the time when these 

 investigations began, and it is believed that the detailed study of definite 

 compounds which is now in contemplation will yield important results. 



PHYSIOLOGY. 



Loeb, Leo, University of Pennsylvania, Philadelphia, Pennsylvania. Grant 

 No. 528. The toxic action of the poison of Heloderma suspectum. 

 (For previous report see Year Book No. 6, p. 218.) $500. 



Professor Loeb reports that during the past year the following work has 

 been carried out in the Laboratory of Experimental Pathology of the Uni- 

 versity of Pennsylvania : 



In collaboration with Miss Elizabeth Cooke, he has investigated — 



( 1 ) The general physiological effects of the venom when it is administered 

 to different species of vertebrates and the macroscopic changes to which it 

 gives rise. 



(2) Some of its physiological properties, viz, its behavior towards heat, 

 filtration, and dialysis. 



(3) Its haemolytic action upon the erythrocytes of animals of different 

 species. 



(4) Place of origin of venom. 



Dr. D. Rivas has investigated the pathological action of certain bacteria 

 obtained from the mouth secretion of Heloderma. 



* E. Merritt : The Physical Review, vol. xxviii, p. 367, 



