200 BOTANICAL GAZETTE [MARCH 
of the season, when the growth of the years had attained such 
thickness as to make this impracticable. Duplicate cuttings were 
made on several trees at intervals of time varying from a few days 
to several weeks. These were always near the former cuttings 
and lateral to them. Rarely were the duplicate cuttings more than 
a few inches from the original ones. One series began in August 
1912 and continued into September of the following year, cuttings 
being taken at least every month. 
The material, as soon as obtained, was properly labeled and 
fixed in Gilson’s fixer of the usual strength. Then after thorough 
washing it was run up through the lower grades of alcohol and 
stored in 65 per cent alcohol until wanted. The above corresponds 
to the methods used in 1910. 
From this point the procedure varied depending on the object 
in view. When it was desirable to know the extent to which growth 
had progressed, or the abundance of starchy material present, 
freehand sections were made with a sharp razor. These were dyed 
with temporary stains and then studied. The HCl-phloroglucin 
stain for lignin, followed by the permanent Haidenhain’s iron- 
hematoxylin stain for cellulose, gave excellent results. Wit 
this combination the extent of growth could be measured and esti- 
mated with accuracy. Chlor-zinc-iodide, as well as various com- 
binations of I-KI, were occasionally used. 
For minute examination of the tissues greater care was taken 
in manipulation. The material was demineralized with hydro- 
fluoric acid and imbedded in celloidin. Sections were obtained 
in this manner 10-15 thin, which served the purposes of the 
investigation. Extensive and comparative histological studies 
were then made and the results tabulated. 
The method described above makes it possible to follow the 
progress of the growth. One obstacle which could not be over- 
come was the inaccessibility of all parts of standing trees. In 
order to check up the results obtained, several trees of different 
ages were felled during the growing season. Accurate stem analyses 
were made of these and the progress of growth was observ 
throughout the tree. These data were then compared with those 
obtained from standing trees. 
