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THE AMERICAN BOTANIST 



constructed dif¥erently. Just why or how they keep the posi- 

 tion given them does not seem to have been investigated, but 

 it will probably be found that the mechanism is similar to that 

 which causes the leaves and leaflets of the sensitive plant to 

 change positions when the plant is touched. 



Redbud Winter. — Meterologists assure us that there is 

 really no such season as Indian summer. After the first frosts 

 of autumn there may ensue one or more weeks of mild weather 

 which commonly receives this name, but this is not a definite 

 season, though the characteristic weather is well known. In a 

 similar way a cold spell in spring, after winter has apparently 

 vanished, is variously named blackberry winter, dogwood win- 

 ter, or redbud winter. Our little winter of this kind comes in 

 May and according to the Monthly Weather Review, from 

 which these facts are gleaned, is known to weather observers 

 as the May dip. The same season is known in England as 

 blackthorn w^inter. In Germany it is supposed to come about 

 the middle of May and the four saints, Marmetus, Pancratus, 

 Servatius and Bonafacius, whose days occur at this time are 

 called in both Germany and France by names which mean ice 

 saints. The redbud winter is almost as well characterized as 

 the opposite season in autumn. It occurs at a time when many 

 birds are migrating and often retards the advance of a bird 

 wave until the number of certain species in a locality becomes 

 so great as to be noticeable. Warblers, especially, seem affected 

 by this drop in temperature and many a bird student owes his 

 first acquaintance with the rarer members of this group to a 

 check in their northward movement due to the redbud winter. 



Concentrating Grape Juice. — The customary method 

 of concentrating fruit juices is to boil them down, during which 

 process the excess water escapes, leaving the other constituents 

 behind. Boiling, however, often changes the flavors of the 

 fruits and other methods of concentrating the juice are desir- 

 able. Recently bottlers of grape juice have taken advantage 



