372 BOTANICAL GAZETTE [May 
THE PREPARATION OF MATERIAL FOR GENERAL 
CLASS USE. 
THE preparation of material for studies of structure, development, 
and embryology, for general course students, or for advanced courses 
where the primary object is to give the student an opportunity to 
examine as large a series of forms as possible, in order to pave the way 
for broader generalizations, and yet allow him to do a considerable 
portion of the work, especially that of the final preparation of the 
specimens, has been a problem of some little difficulty with me, and 
which is perhaps shared to some extent by others. One may depend 
on material simply preserved in alcohol, which the members of the 
class may section as best they can free hand, but this method does not 
give such good preparations usually as sections made by some method 
of precision, though it is a very useful thing to know how to make 
free hand sections well. 
Several laboratories have had recourse to freezing microtomes, OF 
rather to cutting frozen plants with the microtome. This is usually 
done by the instructor or assistant, and the sections are distributed 
to members of the class, where the final treatment is given by eac 
individual. This, it has seemed to me, is an excellent method, and 
while the student does not ordinarily do the sectioning, each one we 
ally has an opportunity to see how the material is oriented, and can 1m 
this way gain a good notion of the relation of the section to the part 
of the plant cut.. So well did I think of this method that I was about 
to introduce it into our laboratories when another method upon which 
I had been working for about two years seemed to me to be in general 
a better one, and it has been largely adopted in my general classes. It 
is understood, of course, that when an individual comes to take UP 
work of the nature of investigation, all the processes involved in the 
preparation of the material are required to be conducted by a 
_ Usually, also, in the advanced courses which precede investigation, — 
each student is called upon to carry several forms through all the 
necessary processes of fixing and manipulation, so that there ins be 
some training in methods preliminary to the later work of investiga 
tion. It this way persons who later do not take up special lines of 
investigation will have an opportunity of studying a larger num) . of 
forms than would be possible if it were insisted that all the. work of 
preparation should be required, and at the same time there 1s some : a 
