The Microscope. 355 



Mature segments of the worm were hardened in Erlick's fluid 

 and alcohol, and cut into transverse and longitudinal sections. The 

 longitudinal sections show the valves (s) of the excretory system in 

 their natural position. 



The nervous system may also be studied by means of sections. 



Ova were taken from the last segment, placed in picric acid and 

 alcohol (50 per cent, alcohol, 100 cc. picric acid, 1.5 grammes) for 30 

 minutes, and mounted in balsam. 



The only published methods of which I am acquainted for the 

 preparation of the tape-worm, will be found in "Manual de 

 Microscopie Clinique," par G. Bizzozero, et Ch. Ferket, in which 

 will be found a process which consists of drying. 



Cornell University. 



ON INDEXING MICROSCOPICAL SLIDES.* 



R. H. WARD. 



^T~^HE Alphabetical Index is, of course, a large and essential 

 -*- portion of this system. Its pages are specially ruled for con- 

 venience in entering titles and numbers, and they have a capacity 

 for several references to each slide, the volume for 2,000 slides 

 having room for about 10,000 references. Thus a leaf preparation 

 may not unlikely be referred to under both popular and scientific 

 names of the plant, and also under several such titles as, " Leaf 

 of — ," "Spiral vessels in — ," "Stomates of — ," " Raphides 

 in — ," etc. But as many simple slides require only two or three 

 entries, the more complex ones will have room for eight or ten. 

 The Index is lettered alphabetically, the number of pages assigned 

 to each letter depending upon the frequency with which that letter 

 occurs at the beginning of English words. Subdivision is accom- 

 plished according to the vowel system of arrangement, whose 

 advantages are familiar to all readers, and which may, by means of 

 a few obvious expedients, be made applicable to slide -catalogues of 

 various sizes. Thus the pages devoted to any letter, as S, are 

 divided into six portions and lettered sa, se, si, so, su, sy; the first 

 portion being for words beginning with S, and having A for their 

 first vowel, and so on for the rest. Further subdivision depends so 

 largely upon individual wants as to be best left optional with the 

 user. But having given a page to the sa words, for instance, it is 

 hardly possible that any thoughtful person could throw all these 



*From a paper on "A Slide-Catalogue," read at the Pittsburg meeting of the 

 Am. Soc. Mic. 



