1889.] MICKOSCOPICAL JOUKNAL. 253 



form of camera, placed at any distance from the table. By magnify- 

 ing -power is meant that special degree of magnification, and no other, 

 which is secured when the camera is placed at the standard distance of 

 ten inches from the paper. If the term " magnifying power" be thus 

 restricted in its use there can be no doubt as to what is meant when it 

 is employed, and therefore no room for discussion on the subject. 



Let me urge you to draw all your objects, at any- rate all those whose 

 beauty or novelty may strike you. The illustrations thus made often 

 help you to identify an object long after it is drawn, and to keep a re- 

 liable record of your work. You will find it useful to make a short 

 note of the locality and date from and on which your object was ob- 

 tained. There isa freshness and accuracy in such memoranda which 

 compensate for the little additional trouble incidental to making them. 

 As an auxiliary to work I am convinced that "the pencil is being un- 

 wisely neglected ;" and when the relative advantages of drawing vs. 

 photograph are dispassionately compared, every microscopist will ad- 

 mit that, for the busy worker, the sketch on paper is, after all, in the 

 present state of development of photo-micrography, the more conven- 

 ient and the more economical of the two. Moreover, the most service- 

 able field for photography lies at the extremes of the table of amplifica- 

 tion, with very low (20 to 70 diam.) and with very high powers (500 to 

 1,500 diam.), and the field for general work except on special subjects, 

 lies in powers ranging from, say, 100 to 450 diameters. 



As the references to the subjects treated in this paper are widely 

 scattered, I subjoin a list of a few articles culled from the journals to 

 which I have had access, and from which I have derived assistance, as 

 well in actual work as in the preparation of this paper. I omit such 

 treatises as Carpenter on The Microscope, Beale's How to work with 

 the Microscope, Davis' Practical Microscopy, Hogg's popular book, 

 etc., because, though they all contain valuable information on the sub- 

 ject, they are readily available to most of us. 



(1) A77ierican Monthly Microscopical Journal : Vol. II, 75? *75 > 

 III, 134, 158 ; V, 21, 207 ; VIII, 215 ; IX, 103, 106. 



(2) Science Gossip : Vol. II, p. 113 ; V, 87 ; VI, 230 ; XIV, 175 : 

 XV, 62 ; XVI, 1S3 ; XVIII, 1, 39, 49, 74, 97, 230 ; XIX, 66, 193, 265 ; 

 XX, 17, 41 ; XXIII, 163. 



Uses of the Microscope in Medicine.* 



By W. D. BIDWELL, M. D., 



LEAVENWORTH. KANSAS. 



It is only within the past few years that the microscope has formed a 

 part of a physician's armamentarium, and even now a large proportion 

 are without it and unaware of the many purposes for which it may be 

 employed. We may therefore run over briefly what may be accom- 

 plished over and above the results of former microscopic work by the 

 use of the instrument. To give methods of preparation of the various 

 substances here mentioned, or even to describe their appearances, would 

 occupy too much space in this article. 



With the microscope we are able to count the number of corpuscles 

 in a given quantity of blood, and determine the proportion of red to 



* Read before the Leavenworth Microscopical Society, Aug. 20, 1889. 



