1900] MICROSCOPICAL JOURNAL. 117 



sometimes developed by long- mordanting-. A slide show- 

 ing them was purposely chosen as a warning to others use- 

 ing the method. — Amos P. Brown. 



Locating Objects on the Slide. — The location of the spe- 

 cial group of cells as mentioned by Prof. Seawell, and in- 

 dicated by his diagram in the note book, and as seen on the 

 slides, can be best described as at "7:30 (or 7^) o'clock," 

 or at "South West," if one prefers the compass method. 

 For full identification, including- the radial distance from 

 the center, an adept would write it at "loc. 7:30 rad. 8," or 

 "loc. S. W., rad. 8 ; " or in recording frequently or tabu- 

 lating, the contractions for "location" and "radius" would 

 be omitted, and the figures only stated, as "7:30, 8, "or "S. 

 W., 8," the meaning- of the figures being indicated by their 

 position where they could mean nothing else. If anyone 

 who has frequent occasion to refer to slides, and who has 

 not used this method of location, will do himself the favor 

 of getting it thoroughly in mind and hand, so as to give it 

 a fair trial in practice, and find how convenient and practi- 

 cal it is for cases not requiring the Maltwood finder, he will 

 be likely to wonder why everyone does not use it. These 

 precautions are to be observed : 



(1). Decide whether you will record the actual location 

 as seen with a simple lens, or the apparent location as seen 

 (inverted) in the compound microscope, and always follow 

 the same rule ; and specify which you mean, at least in the 

 few doubtful and difficult cases, when off ering records to 

 those who do not know your habit. The latter method, re- 

 cording as it always looks in the microscope, seems to me 

 simplest and most rapid, and least liable to mistake, as all 

 observations and readings are direct and without a con- 

 stant allowance for reversal ; you must, however, allow for 

 reversal of your record, when looking at the slide with the 

 naked eye or under a simple microscope. In the slide un- 

 der consideration, the two most notable regions happen to 

 be just opposite each other, one in the mount at 7:30, but 

 appearing in the microscope at 1:30, and the other exactly 

 the reverse. (2). In a specimen considerably smaller than 

 the cover-glass, especially if eccentric to it, it may be best 



