MICROANALYTICAL AND BACTERIOLOGICAL LABORATORY 425 



substance must be properly mounted upon a slide. There are many sub- 

 stances which it is convenient to have on hand ready mounted for imme- 

 diate microscopic examination. These are to be kept in a second smaller 

 cabinet, known as the cabinet for microscopic slides. 



2. Cabinets of Microscope Slides. The cabinets of various sizes can be 

 obtained from dealers in microscopic supplies and are intended to hold 

 slide mounts for microscopic examination. The slide mounts are ob- 

 tained from various sources. Many will be prepared by the analyst, 

 from times to time. Others will be secured from dealers in scientific 

 instruments and supplies who generally furnish lists of the slides which 

 they offer for sale, more especially representing the following groups of 

 organisms and tissues. 



(a) Bacteria. Molds and other fungi. Protozoa. 



(b) Desmids, diatoms, and other low forms of algae. 



(c) Embryological slides. 



(d) Vegetable tissues of all kinds. 



(e) Animal tissues, normal and pathological. 

 (/) Crystals, minerals, earths, etc. 



The State and Local Boards of Health may furnish slides of the principle 

 disease germs, etc., free for demonstration purposes, and such a cabinet 

 should be added to the exhibit. The ready prepared sets of slides 

 should be carefully selected so as not to encumber the exhibits with 

 things of little or not practical use. The slides will be of inestimable 

 value in some of the analytical work. One medium size slide cabinet 

 will be sufficient as a beginning. A complete index to the slides must 

 be prepared and such index must be conveniently usable. 



3. Photo-micrographs. There should be a photo-micrograph of each 

 and every article mounted upon a microscope slide. The prints should 

 be mounted upon suitable cards and every photograph should be very 

 carefully and accurately labelled. It would be desirable to have two 

 sets of these photographs. One set in a filing case, in alphabetical se- 

 quence according to common English names. The other set pasted into 

 a book, in groups following the appended outline. The book would be 

 very desirable for quick reference and for comparative demonstration 

 purposes. 



It is suggested that the articles in the three divisions of the exhibit, 

 above explained, should be arranged in alphabetical sequence according 

 to well established and generally recognized common English names, ex- 

 cepting that a certain amount of special grouping is desirable or neces- 

 sary, as already explained. As the exhibit gains in size it may become 

 necessary to adopt some other system of arrangement. 



For the benefit of those who are entrusted with the building up of an 



