NOVEMBEE 7, 1913] 



SCIENCE 



665 



engineering; Carl Bertram Harrop, E.M., to 

 be assistant professor of ceramic engineering; 

 Aubrey Ingerson Brown, M.E., to be instructor 

 in mechanical engineering. Mr. Franklin 

 Wales Marquis, M.E., of the University of 

 Illinois, has been appointed professor of steam 

 engineering to succeed Mr. E. A. Hitchcock, 

 M.E., who resigned last spring to accept a 

 position as sales engineer with E. W. Clark 

 & Co. 



Mr. G. D. Horton, M.S. (Tale, '13), has 

 been appointed instructor in bacteriology in 

 the Oregon Agricultural College. 



Miss E. M. Pinnet, formerly instructor in 

 zoology, at the University of Kansas, has been 

 appointed demonstrato]" in biology in Bryn 

 Mawr College, to succeed Dr. Harriet Ran- 

 dolph, who is at present in Europe. 



The following appointments have been made 

 at the University of Birmingham: Mr. L. J. 

 Wills, assistant lecturer in geology and geog- 

 raphy; Mr. David Brunt, lecturer in mathe- 

 matics (to succeed Mr. S. B. McLaren) ; Dr. 

 0. L. Boulenger, reader in helminthology ; Mr. 

 H. G. Jackson, assistant lecturer in zoology. 



DISCUSSION AND COBBESPONDENCE 



LABELING MICROSCOPIC SLIDES 



To THE Editor op Science: Two things are 

 absolutely essential to properly prepared 

 microscopic slides; these are permanent labels 

 and cleanliness. I have been interested in two 

 notes that have recently appeared in Science, 

 namely, one by Zea Northrup in the July 25 

 issue and, the other, by Ernest S. Reynolds, in 

 the September 12 number. The paper labels 

 usually affixed to the slides of a study or loan 

 collection soon become soiled and the data 

 more or less effaced. To obviate this, several 

 years ago I commenced to use small and very 

 thin paper slips upon which the data were 

 written in " Higgin's Waterproof (Black) 

 India Ink," placed under the cover-glass at 

 one of the angles and in this way mounted 

 with the specimens. I have observed this 

 method in use at several institutions. This 

 technical procedure permits dipping of the 

 slides into water and their subsequent clean- 



ing and polishing with a soft cotton cloth. 

 The covering of the India ink label with 

 balsam and cover-glass, as recommended by 

 Reynolds, is an excellent method. I do not 

 think it wise to trust to " merely printing or 

 writing the necessary description upon the 

 slide with India ink" as recommended by 

 Northrup. A person can not always be sure 

 that the writing surface is free from oily mat- 

 ter. Disappointment frequently attends this 

 procedure. For some time I have used the 

 following method: The essential data are 

 neatly written or printed across one end of 

 the slide as close as possible to the cover- 

 glass and, after the ink has dried, a thin layer 

 of Canada balsam in xylol — two to one — is 

 painted with a camel's hair brush across the 

 slide over the label. After the balsam has be- 

 come thoroughly hardened the slide can be 

 dipped into cold water and cleaned with a 

 soft cotton cloth, as above. Care should at 

 all times be taken to avoid having the slides 

 come in contact with alcohol or xylol. Should 

 such a thing happen the surface of the bal- 

 sam can be restored by reapplication of the 

 thin balsam. The first slide of a series or set 

 should bear a paper label as well as the ink 

 inscription. 



Frank E. Blaisdell 

 Surgical Pathological Laboratory, 

 Medical Department of 

 Stanford TJniversitt, 

 San Francisco, Cal. 



a northerly record for the free-tailed bat 

 On the morning of August 15, 1913, 1 picked 

 up a live male free-tailed bat {Nyctinomus 

 mexicanus Saussure) on the pavement on the 

 main business street of Lincoln, Nebraska. It 

 was huddled against the wall at the comer of 

 what is probably the most brilliantly lighted 

 building on the street where it was presumably 

 attracted by the illumination the previous 

 night. The specimen is now in the author's 

 collection where it has been seen by Mr. 

 Vernon Bailey, of the U. S. Biological Survey, 

 who has verified the determination. 



This bat normally occurs in the United 

 States in the Lower Sonoran fauna of Texas, 



