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 g-roup of cells as mentioned by Prof. Seawell, and in- 

 dicated by his diag-rara 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 fig-ures 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 g-etting it thoroug-hly in mihd and hand, so as to g-ive it 

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

 cal it is for cases not requiring- the Maltvvood 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 offering- 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 reading-s 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 reg-ions 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 



