The specimens must be kept in air-tight jars, and crystals of thymol added to prevent growth of moulds. This is sometimes very difficult, and it becomes necessary to change the discolored fluid for clear. I have found the rectangular museum jars best adapted for the preservation of Kaiserling specimens. I use a wooden top which fits over a thick piece of felt cut just the size of the jar, which in turn fits over a piece of dental rubber cut to fit the jar. The jar is placed upon a wooden bottom which has upright steel rods at the corners, that pass through holes in the wooden top, and have a screw-thread so that they can be fitted with screws, which when screwed down hold the wooden top, felt and rubber sheeting tightly in place, making the jar air-tight, but giving a top easily removable. Very beautiful specimens can be secured by the Kaiserling method, and they can be kept for several years, but sooner or later the color-effect is lost. Light, heat and exposure to the air cause a loss of color. Some workers prefer the following in place of Sol. I:— Hot water 2,000 cc. Sodium sulphate 40 grms. Magnesium sulphate 40 grms. Sodium chloride 20 grms. When salts are dissolved and solution cool add 200 cc. of formalin. Melnikow-Raswedenkow Method:— Sol. I.—Water 100 parts Formol 10 parts Sodium acetate 3 parts Potassium chlorate 0.5 part Leave in this 1-2-3-4-5 days, according to size of specimen. Large organs must have solution injected into vessels. Sol. II.—95 per cent alcohol, until color is restored. Sol. III.—Preserve in: Water 100 parts Glycerin 60 parts Potassium acetate 30 parts Pick’s Method:— Sol. I.—Water 1,000 cc. Formol 50 cc. Carlsbad salts 50 grms. Then transfer to 80 and 95 per cent alcohols, as for Kaiserling, and preserve in water 9,000 cc., glycerin 5,400 cc., sodium acetate 2,700 grms. =Westenhoeffer’s method= of preserving uric-acid: formol vapor 4-24 hours, then 80-90 per cent alcohol containing mercuric oxide, and preserve in glycerin to which some mercuric oxide covered by cotton or absorbent paper has been added. =Claudius’s Method.= The specimen is placed on a grating in a closed vessel containing a concentrated solution of ammonium sulphate, an abundance of the crystals being left on the bottom of the vessel. Carbonic acid or illuminating gas is passed through the ammonium sulphate solution for 48-72 hours, and the specimens are then preserved in the same solution. My experience with this method has not been satisfactory.