92 The Philippine Journal of Science 1917 
sities of natural illumination. As no measurements were made 
of the light intensity employed in this work, the results are 
qualitative and need not be considered here. 
Edmond Rosé(19) has done considerable work on photosyn- 
thesis, but his interest was not primarily directed toward the 
study of the relationship between assimilation and light intensity, 
and his quantitative data are of no interest here. 
The earlier work on this subject has been discussed critically 
by Reinke(18) and by Pantanelli,(16) who have shown con- 
clusively that it failed to established the relation between assim- 
ilation and light. It requires, therefore little more than brief 
mention here. 
Von Wolkoff (23) studied the effect of different light intensities 
on the rate at which gas bubbles were liberated from plants 
immersed in water containing carbon dioxide and found a very 
close proportionality between illumination and reaction velocity. 
He worked with feeble light intensities and only over a very 
small range. It is clear from the work of Reinke(18) and of 
Pantanelli(16) that the relation between bubble emission and 
light varies with different illumination intensities so that work 
over a small range cannot establish a general law. 
The work of van Tieghem (21) has been quoted as showing that 
carbon dioxide assimilation is proportional to the incident light 
intensity. This author gave the results of a single experiment 
with a submerged water plant and concluded that the accelera- 
tion was proportional to the light intensity. His method of 
reaching this conclusion is not entirely clear. 
The gasometric measurement of the assimilation of land plants 
with varying light by Miiller(15) may be disregarded because of 
Pantanelli’s apparently valid criticism of the experimental 
method employed. We have been unable to consult this work. 
Reinke(18) has shown that the method of experimentation 
employed by Famintzin (8) is also open to objections. The results 
of the latter, however, do not show a proportionality between 
light intensity and assimilation. | ' 
The experimental results of Timiriazeff(20) on the influence 
of light on photosynthesis in Potamogeton lucens and certain land 
plants (species not stated) have been criticized by Pantanelli(16) 
because of the methods employed. Owing to faulty experimenta- 
tion and the method of presentation of data in the original paper, 
this work has received scant attention. However, as the results 
show good general agreement with the works of Reinke, (18) 
Pantanelli,(16) and Matthaei,(14) and his interpretation is better 
than that of the other workers, we have summarized the results 
