Proceedings and List of Papers read. 419 



the oxide is still active, or it may be dried over calcium chloride or 

 even exposed to a vacuum for some time, and it is still active, but if 

 heated to 55 for seventeen hours then its activity is gone and a pic- 

 ture the reverse of the former one is obtained, that is, the oxide is 

 now quite inactive, but the metal itself is very slightly active. Oxides 

 of zinc, cadmium, and magnesium, if wetted with peroxide of hydrogen 

 solution, act in the same way and retain their activity with great 

 pertinacity. 



From the foregoing experiments it is then concluded that hydrogen 

 peroxide is the agent which directly or indirectly causes the changes 

 in the photographic plate. 



This investigation has been carried on in the Davy-Faraday labora- 

 tory, and I would again tender my best thanks to the managers of the 

 Royal Institution for allowing me to work there. My thanks are also 

 due to Mr. 0. F. Block who has most efficiently helped in carrying 

 on the above experiments. 



March 9, 1899. 

 The LORD LISTER, F.R.C.S., D.C.L., President, in the Chair. 



A List of the Presents received was laid on the table, and thanks 

 ordered for them. 



The following Papers were read : 



I. "A Preliminary Note upon certain Organisms isolated from 

 Cancer, and their Pathogenic Effects upon Animals." By 

 H. G. PLIMMER. Communicated by Dr. ROSE BRADFORD, 

 F.R.S. 



II. " On the Gastric Gland of Mollusca and Decapod Crustacea ; its 

 Structure and "Functions." By Dr. C. A. MACMUNN. Com- 

 municated by Professor M. FOSTER, Sec. R.S. 



III. " On the Structure and Affinities of Matonia pectinate, R. Br., with 

 Notes on the Geological History of the Matoninese." By A. C. 

 SEWARD, F.R.S. 



IY. " A Sugar Bacterium." By Professor MARSHALL WARD, F.R.S., 

 and Professor REYNOLDS GREEN, F.R.S. 



V. " Note on a new Form of Light Plane Mirrors." By A. MALLOCK. 

 Communicated by LORD RAYLEIGH, F.R.S. 



VOL. LXIV. 



