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 dupUcate 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. With 

 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 io-15/i 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 observed 

 throughout the tree. These data were then compared with those 

 obtained from standing trees. 



