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NOTES AND MEMORANDA. 
Examination of Wool by the Microscope. — A valuable report 
has beeD published in the ' Bulletin of the National Association of 
Wool Manufacturers' (an American body), which is by Dr. J. J. 
Woodward, the distinguished microscopist, and Dr. J. L. Leconte. 
The ' American Naturalist ' furnishes us with the following account 
of the results arrived at by these two gentlemen : — The kinds of 
hairs observed and described by the commission may be con- 
veniently arranged in three groups. First, woolly hairs. These 
mostly extend " from half an inch to several inches in length, 
without any medulla, and without perceptible taper. They present 
(especially in the wool of the sheep), at frequent but irregular inter- 
vals, well-marked, one-sided, more or less spirally arranged thicken- 
ings of the cortical substance, which gives to the wool its curly 
character. The mean diameter of each hair varies from ^^^^ to the 
ToVo inch, or even less ; and the scales of the cuticle are so 
arranged that their free edges project somewhat, forming well-marked 
imbrications, of which usually from fifteen to thirty can be counted 
in the -y^o inch." Such hairs constitute the wool of com- 
merce, originally limited to the sheep but now applied to the goat, 
camel, and llama, and similar hairs have long been known to be 
mixed with the straight hair of various animals, such as the " deer, 
hare, rabbit, beaver, otter, seal, lion, tiger, certain varieties of dog, 
and some foreign breeds of oxen." All these hairs are so much alike, 
structurally, that it is believed they should all be designated as wool, 
and it is not claimed that the animal from which they were derived 
can be uniformly and reliably determined by the microscope. Ob- 
viously some of these varieties not now recognized as wool might in 
the future become of sufficient commercial importance to require 
either the legalization of them all as " wool," or the discovery of more 
complete methods of discrimination. Second, straight hairs. These 
are often shorter, " much thicker at their base, and taper rapidly 
towards the point. The medulla occupies a large proportional part 
of the whole hair, and the free edges of the scales of the cuticle, 
which are so disposed as to form from twenty to forty imbrications to 
the of an inch, lie quite smoothly upon the surface of the hairs, 
so that their contours, as seen under the microscope, closely approxi- 
mate continuous lines. These characters are so well marked that the 
coarser hairs of the cow and calf can readily be distinguished from 
the woolly hairs of any of the wool-bearing animals." Naturally 
mixed with the wool of the sheep, however, especially with the 
inferior grades, and with that of the goat, forming the " outer coat " 
of the goat, are coarse, straight hairs, so closely resembling some of 
the hairs of the cow or calf that their discrimination presents great 
difficulties ; and such hairs, even when derived from the wool-bearing 
animals, cannot be recognized as wool by the microscope. The per- 
centage of " wool," therefore, as determined in mixed fabrics, by a 
microscopical count of hairs, would probably be underrated in a 
certain proportion of cases. In case all woolly hairs which are 
" more or less crispy, curled, or frizzled," should be legalized as 
wool, it would probably be convenient to make an exception, ad- 
