1887 ] Botany. 77 
hundred cases the circumference of the trunk! was carefully 
measured a few inches below the point of branching, and also 
the circumferences of the branches a few inches above the same 
int. € measurements were made a little above and below 
the crotch in order to avoid the extra swelling usually occurring 
at that point. In each instance the area of the trunk circumfer- 
ence was compared with the sum of the areas of the limb cir- 
cumferences. In this way it was found that the limbs just above 
point of branching on the average contain eleven per cent. more 
wood than does the trunk just below the same point. This gen- 
eral fact may be somewhat interesting, but it is not very signifi- 
cant. In the economy of the tree, constantly strained and bent 
by the wind, strength is far more important than mere bulk. In 
order to determine the relative strength of the tree-stem and its 
branches, the cubes of the trunk circumferences were compared 
with the respective sums of the cubes of the corresponding limb 
circumferences.* This comparison showed that in ninety-five per 
cent. of the four hundred observed cases the trunk just below 
the crotch was stronger than all the limbs just above the same 
point. And on the average the trunk was found to be thirteen 
per cent. stronger than the sum of all its branches coming from ` 
one point. Now practically just above the crotch the branches 
have to support the same burden as does the trunk just below 
that point, then why is the trunk made stronger than its limbs ? 
Well, even if a branch or several branches are broken by the 
wind, the tree can still grow and reproduce its kind, but if the 
trunk be broken the tree receives a much greater injury. Thus 
in general although the limbs of a tree are more bulky than the 
main stem, yet at practically the same elevations the trunk, by 
the constant action of the wind, is kept decidedly stronger than 
all its branches.—B. F. Hoyt, Manchester, Towa. 
The Article “ Schizomycetes” in the Encyclopedia Brit- 
Bacteria only, evidently agreeing with many modern writers 
in considering the Yeast Fungi (Saccharomycetes) as having 
strong cteria. In a short 
historical introduction; it is stated that “ Leeuwenhoek figured 
Bacteria as far back as the seventeenth century, and O. F. Müller 
knew several important forms in 1773, while Ehrenberg in 1830 
had advanced to the commencement of a scientific separation 
t Any relatively large part of the tree having branches was considered as a trunk, 
and several observations were frequently made among the larger limbs of the same 
tree. ; 
2 According to an established principle of mechanics, the strength of solid bodies 
of same form and substance is in proportion to the cubes of their like dimensions. _ 
