SCAMMON: RECORDING EMBRYOLOGICAL MATERIAL. 185 



present a neat appearance, and have been found very satis- 

 factory, not only for numbering museum jars, but slide boxes 

 and carriers as well. They may be obtained in either black 

 or red. 



Should the embryo be sectioned, the slides upon which it 

 is placed bear in the upper right-hand corner a fraction writ- 

 ten with a diamond pencil (fig. 2). The upper number is 

 the accession number of the embryo ; the lower number indi- 

 cates the position of the slide in the series of slides made 

 from the particular embryo. This device, the credit for 

 which belongs to Mr. R. G. Hoskins, former fellow to the 

 department, insures the identity of each slide, and to a great 

 extent prevents the loss of slides. The slides may also be 

 labeled if desired. In this collection only the first slide of 

 the series is labeled. The label is written in India ink on 

 thin, tough paper, exactly the size of an ordinary square 

 cover-glass, 22 mm by 22 mm. This label is then soaked in 

 creosote and mounted in balsam under a cover, in the same 

 manner as a section might be. Such a label never fades or 

 becomes detached from the slide, and is a great improve- 

 ment over the old-fashioned paper label. 



After experiments with a number of styles of containers, 

 the boxes holding 100 slides and having about the dimensions 

 of an ordinary quarto volume have been found the most satis- 

 factory. Such containers are reasonable in price, and may be 

 had of any of the well-known dealers in microscopical supplies. 

 These boxes are serially numbered on the backs, and are 

 placed on shelves, as books might be. A large card just fits 

 into the lid of each box (fig. 3). This card is ruled off into 

 three columns, in which are recorded the accession numbers, 

 the number of slides, and a brief statement of the material 

 of the sets contained in the box. Such cards are only slightly 

 attached to the box lid, and may be removed if desired. The 

 number of the box in which each set of slides is placed is 

 noted, in pencil, in the "Container" space on the proper data 

 card (see fig. 1). While no strict classification of the slides 

 is attempted, because a slide may always be located from the 

 data card, still a general classification of slides into large 

 groups is possible, and will suffice for a long period without 



