Quantitative Experiments on the Effect of Formal- 
dehyde on Living Plants . 1 
BY 
SARAH M. BAKER, 
Quain Student at University College , London . 
With Plates XXX and XXXI and four Figures in the Text. 
HERE are no chemical problems so fascinating or so elusive as those 
A which are continually presenting themselves in connexion with the 
metabolism of living plants and animals. The complexity of the reactions 
involved, and the microscopic dimensions of the tissues in which they take 
place, render an exact study of any one process an exceedingly difficult 
task. In general, it is only by the accumulation of a mass of more or less 
indirect evidence, obtained by many observers working from different stand- 
points, that any indication can be obtained of the course of a reaction as it 
occurs in living tissues. 
The present investigation was undertaken in the hope that some light 
might be thrown on the problem of photosynthesis by a careful and detailed 
study of the action of formaldehyde on living plants. These hopes have 
only in part been realized, as the process appears to be much more 
complicated than has often been supposed. 
Previous Work on the Subject. 
Almost all the chemical theories which, from time to time, have been 
brought forward to explain the process of carbon assimilation in green 
plants, begin from the assumption that formaldehyde is the first product in 
the reduction of carbon dioxide. 
From a purely chemical point of view, much evidence is available that, 
if a suitable source of energy is provided, carbon dioxide can be converted 
into carbon monoxide or formaldehyde in the presence of water, and thence 
in alkaline solution to ketoses and aldoses. The recent work of Stoklasa 2 
1 Thesis approved for the Degree of Doctor of Science in the University of London. 
2 Stoklasa and Zdobincky : Biochem. Zeit., 1911, xxx. 433-56; and Stoklasa, Sebor, and 
Zdobincky : Biochem. Zeit., 1912, xli. 333-72. 
[Ann&ls of Botany, Vol. XXVII. No. CVII. July, 1913.] 
