340 CABINETS AND TRAYS FOR SPECIMENS [Ch. X 



Weber, answers well. For ordinary writing it should be diluted 

 with one-third its volume of water and a few drops of strong ammonia 

 added. 



If one has a writing diamond it is a good plan to write a label with 

 it on one end of the slide. It is best to have the paper label also, as it 

 can be more easily read. 



The author has found stiff cards, 12^ X 7§ cm., like those used for 

 cataloguing books in public libraries, the most desirable form of "cata- 

 logue. A specimen that is for any cause discarded has its catalogue 

 card destroyed or stored apart from the regular catalogue. New cards 

 may then be added in alphabetical order as the preparations are made. 

 In fact a catalogue on cards has all the flexibility and advantage 

 of the slip system of notes. 



Some workers prefer a book catalogue. Very excellent book cata- 

 logues have been devised by Ailing and by Ward (Jour. Roy. Micr. 

 Soc, 18S7, pp. 173, 348; Amer. Monthly Micr. Jour., 1890, p. 91; 

 Amer. Micr. Soc. Proc, 1887, p. 233). 



The fourth division has been added, as there is coming to be a strong 

 belief, practically amounting to a certainty, that there is a different 

 structural appearance in many if not all of the tissue elements, de- 

 pending upon the age of the animal, upon its condition of rest or 

 fatigue; and for the cells of the digestive organs, whether the animal 

 is fasting or full fed. Indeed as physiological histology is recognized 

 as the only true histology, there will be an effort to determine exact 

 data concerning the animal from which the tissues are derived. (See 

 Minot, Proc. Amer. Assoc. Adv. Science, 1890, pp. 271-289; Hodge, 

 on nerve cells in rest and fatigue, Jour. Morph., vol. VII (1892), 

 pp. 95-168; Jour. Physiol., vol. XVII, pp. 129-134; Gage, The Pro- 

 cesses of Life revealed by the Microscope; a Plea for Physiological 

 Histology, Proc. Amer. Micr. Soc, vol. XVII (1895), pp. 3-29; 

 Science, vol. II, Aug. 23, 1895, pp. 209-218. Smithsonian Insti- 

 tution, Report for 1896, pp. 381-396. 



Cabinet for Microscopic Preparations 



§ 530. While it is desirable that microscopic preparations should 

 be properly labeled and catalogued, it is equally important that they 



