Mar. 1903. | LUMINOSITY IN PLAN'S. 337 
during the metabolism, or more especially the respiratory 
katabolism of the cell, the slow oxidation of which gives rise to 
light, or whose action on other substances also in the cell, gives 
rise to ight. Luminosity, according to this view, therefore, 
is a chemical production of light, not a specific property of 
the living protoplasm. Pfeffer’s view is closely allied to 
Dubois’ theory for the luminosity of insects and _ fishes, 
though no substances, such as luciferin, and luciferase, which 
is of the nature of an enzyme, have been isolated in the case 
of plants, as in the case of Pholas dactylus, 
Of what significance luminosity is to plants it is difficult 
to say. It may not be of any direct use, except as a means 
of getting rid of waste products by burning them, so to speak. 
But since luminosity in fishes and insects seems to possess a 
significance it seems natural to search for the same in the 
plant world. Further research may reveal much, however, 
that is now incomprehensible. 
Mr. JAMES WHYTOCK showed a series of cut flowers from 
Dalkeith Palace Gardens. 
Dr, R. StTEwarT MacpouGAa.t exhibited (1) a section of 
Pier Prop from Felixstowe ruined by Zeredo; (2) Branch of 
apple tunnelled by caterpillar of Zeuzera esculi, with 
caterpillar i situ from Essex. 
Dr. A. W. BortHwick exhibited a series of specimens of 
trees and shrubs in various stages. 
Mr. R. L. Harrow showed the following plants in flower 
from the Royal Botanic Garden :—Corydalis bulbosa, var. 
densiflora, Galanthus nivalis, var. poculiformis, Iris histrioides, 
Iris x per-sind, Iris x sind-per, Iris reticulata, var. Krelagei, 
Tris sophonensis, Primula malacoides, Ranunculus Ficaria 
(with mottled leaves), Saaifraga apiculata, S. Boydii, 8. 
Boydii, Faldonside var., S. juniperifolia, S. oppositifolia, S. 
Pauline, S. Petraschii, S. scardica. 
TRANS, BOT, SOC. EDIN, VOL. XXIII. 24 
