TEACHERS DEPARTMENT. 
263 
in any position. It is further one which many pupils may con¬ 
struct for themselves and so carry out experiments inde¬ 
pendently. L. 
A simple modification of Detmer’s experiment to demonstrate 
the need of light for photosynthesis is given by King in Torreya 
for April, 1905. Miss Haug (Bot. Gaz November, 1903) has 
called attention to a source of error in the experiments as de¬ 
scribed by Detmer, where two pieces of cork are pinned opposite 
to each other on the two surfaces of the leaf. By this arrange¬ 
ment there is a possible exclusion of carbon-dioxide as well as of 
sunlight. The modification proposed by King is to substitute 
for the corks “ narrow strips of black cloth about as coarse- 
meshed as cheese-cloth/’ By this means the carbon-dioxide finds 
ready access to the tissue by diffusion through the cloth, while 
light is effectually excluded. No starch is formed under the strips 
of cloth. C. S. G. 
REVIEWS. 
Organography of Plants. By Dr. K. Goebel. English translation by 
Isaac Bayley Balfour. Oxford: The Clarendon Press. Part I. Gen¬ 
eral Organography. Pp. xvi 270. 1900. Part II. Special Organ¬ 
ography. Pp. xxiv -f- 708. 1905. 
Organography and plant physiology are closely interwoven departments 
of botany. We may study the effect of various factors of environment 
on the structure and function of plants, or we may restrict our field and 
change our view-point, confining our study to the organs of the plant and 
endeavoring to explain the observed facts. The latter is the scope and 
point of view of Dr. Goebel’s two volumes. The keynote to the work, 
stated in the preface to Part I, is that “ the configuration exhibited by 
plants is a part of their life phenomena,” and, “ that to recognize the 
factors which bring about the development of say a leaf with one side 
larger than the other is infinitely more important than to construct a phy¬ 
logenetic hypothesis unsupported by facts.” Of course the method is that 
of experiment 
Part I deals with general principles. Part II gives the experiments 
and facts upon which the principles are based. Every page is of interest. 
Besides being a monumental contribution in itself, the work will be of 
great value as a stimulus to further research. It will have special value for 
teachers, correcting many false or inadequate notions, and suggesting 
many problems which may' be undertaken and successfully prosecuted 
without the aid of costly apparatus and elaborate technique. The book 
