Reconstruction of Elementary Botanical Teaching. 145 
been studied mainly from the point of view of external morphology. 
The functions of cotyledons are pointed out, it is true, and facts 
like the enlargement of the haustorium in the date seed, for 
example, which are revealed by a crude morphological examination 
and are of obvious physiological significance. But how often is 
attention drawn to the equally striking changes occurring in the 
wheat grain, where the haustorium does not enlarge ? Yet the 
semi-fluid condition to which the endosperm is reduced is readily 
observed. It is a simple matter to examine its condition in the 
later stages microscopically and to apply simple tests, including the 
test with Fehling’s solution for reducing sugars. The facts thus 
brought home give a good basis for further instruction regarding 
the digestive processes at work and lend significance to the 
remarkable semipermeable properties of the grain-coat. Especially 
for medical students would this aspect of germination have far 
more interest as well as practical value, than the changes of form, 
which are more of purely botanical than of general biological 
interest. 
Again, in the study of Pellia attention is usually concentrated 
on the mature form and morphological development of the various 
organs. But from every point of view one of the most fascinating 
features is the growth and nutrition of the sporogonium as a 
parasite upon the thallus. The digestive epithelium of the foot 
and the distribution of starch are particularly striking. A com¬ 
parison of different stages reveals further the changes occurring 
in thallus and sporophyte—the enlargement of the foot, digesting 
and compressing the tissue below and around it, the hypertrophy 
of thallus and archegonium and the transfer of starch from the 
thallus and its accumulation in the seta and capsule. 
This example suggests immediately certain practical con¬ 
siderations which are really fundamental. To study Pellia in 
this way means spending more time on Pellia in the laboratory. 
Suitable material must be preserved at the right times of year, and 
the different stages examined and compared. To bring out 
satisfactorily the growth changes, drawings must be made to 
approximately the same scale. In fine, it means a more thorough 
study of the whole life history and, I am inclined to think, leads 
inevitably to a modified type system, in the sense that fewer plants 
must be selected for the practical course, relegating to lectures and 
demonstrations the presentation of a more general view of the 
vegetable kingdom. 
