1876. ] Microsvopy. 565 
of the wool of the sheep some are occasionally found which so closely re- 
semble the softer hairs of the cow or calf that the investigators confess 
themselves unable to discriminate between them in all instances. Hairs 
of this description are therefore more properly classed as doubtful, than 
included in either of the other groups. 
ANIMAL AND VEGETABLE CELLULOSE AND STarcu.— Mr. Thomas 
Taylor has contributed to a late Monthly Report of the Department of 
Agriculture some interesting experiments by which starch-like bodies 
are artificially produced. On a fibre of cotton is placed a drop of a 
strong, amber-colored tincture of iodine, followed by a drop of commer- 
cial muriatic acid, and immediately afterwards by a drop of concentrated 
sulphuric acid. The combination of the sulphuric acid with the water of 
the muriatic causes the liquid to boil for two or three seconds, and the 
cellulose or cotton fibre is changed, as shown under a power of about one 
hundred diameters, into the form of disks or beads of a well-defined blue 
color. A similar change can likewise be produced in flax, and in a vari- 
ety of vegetable tissues. Fresh animal tissues yield a somewhat similar 
result, brain, heart, liver, muscles, etc., having been successfully experi- 
mented upon. Fibrine of blood, both human and bird’s, dissolved in 
caustic potash and precipitated by acetic acid, gives well-characterized 
granules, a result which is confirmed by hundreds of experiments. 
ARRANGED PorLens.— Mr. J. A. Langstroth has presented to the 
San Francisco Microscopical Society slides having pollen from different 
species of flowers, arranged on the same slide for convenience of com- 
parative study. 
Errrcr or APERTURE ON DEFINITION. — Mr. J. Zentmayer, in a 
very clear lecture on the elementary properties of lenses, published in 
the Journal of the Franklin Institute, May and June, 1876, calls atten- 
tion prominently tò the confusion of images necessarily attendant upon 
8° apertures, except when viewing absolutely flat objects, from the 
“ereoscopic character of the images formed by different portions of the 
Surface of the lens, the image formed by pencils transmitted by one side | 
of the lens being unavoidably different from corresponding images formed 
7 the opposite side of the lens. 
Microscoprcar EXAMINATION oF Crupe Druas. — Prof. M. W. 
Harrington, whose well-known success in this branch of study gives in- 
terest to any production for which he is responsible, being not yet ready 
© Publish his work on the Identification of Vegetable Drugs, Foods, and 
Tres, has caused the publication in pamphlet form (by John Moore, 
Publisher, Ann Arbor, Mich.) of the Introduction and Analytical Tables 
4 mth which the book will be furnished. The brief introductory part con- 
: “8 a few excellent general suggestions in regard to this kind of work, 
While the analytical tables are a novel and able application of the meth- 
ods of the artificial keys of modern works on botany to this field of mi- 
cToscopica] research, The tables are published. now, and in this form, 
