120 Moore: The study of winter buds 



Microscopic study of growth 



Collecting : Collections of material were made during the latter 



part of each month from November to April inclusive. Buds 

 were cut from the high and low parts of each tree with tlie long 



pruning shears. The trees from which the buds were taken were 

 situated in exposed and in sheltered places. In each case, how- 

 ever, the buds were cut from mature shrubs or trees and not from 

 saplings or young growths. 



Fixing: These methods are given in considerable detail be- 

 cause the varied character of the buds offered peculiar difficulties 

 in fixing and cutting. In general, the bud scales were removed 

 to the young leaves and the remainder of the bud was fixed entire. 

 In the horse-chestnut the two outer whorls of leaves, and in the 

 beech three lower leaves were also removed. Buds were placed 

 directly in 20 per cent, alcohol and then passed successively 

 through 40, 60, 80, 95 per cent, and absolute alcohol, remaining 

 in each grade 24 hours. To insure perfect dehydration the abso- 

 lute alcohol was changed once. The material was brought grad- 

 ually into pure cedar oil bypassing through the grades of alcohol 

 and cedar oil, 33 and 6(^ per cent cedar oil, 24 hours each. After 

 remaining in cedar oil a few days, it was then carried through the 

 grades of paraffin and cedar oil, 33 and 66 per cent, paraffin, to 

 pure paraffin, melting point 54°, in which it was finally imbedded. 



Staining: The budS were sectioned with a Minot-Zimmer- 

 mann revolving microtome. In most cases they were cut 10// in 

 thickness. The exceptions to this were the woody and hairy 

 buds, the hickory, oak, basswood, birch, and alder. These buds 

 were cut from 25 to 50 /i in thickness, depending upon the char- 

 acter of the bud. This greater thickness of the sections was not 

 disadvantageous, since an outline study of the growing point, and 

 not a cytological study, was desired. All sections were mounted 

 serially. The usual method of staining with Delafield's haema- 

 toxylin was followed in all cases except one. The basswood sec- 

 tions are not well stained by this method because of the muci- 

 laginous nature of the buds. The water used in the Delafield stain 

 dissolves the mucilage which spreads over and obscures the tis- 

 sue. A satisfactory stain was secured by using a solution of 

 Bismarck brown in absolute alcohol. After the slides came from 



