3U The Microscope. 



the slip, spread it out thin, but not too thin; set the slides in a 

 place with a temperature not lower than 78° F., and cover so as to 

 exclude dust and light. As soon as the blood is dry the crystals will 

 appear. 



"Crystals of urea are dissolvable by the moisture of the atmos- 

 phere, so that it is necessary to mount them without delay as soon as 

 the blood has sufficiently dried. The mounting of the urates can be 

 deferred longer before completing. The crystals are mounted in 

 balsam, and should be viewed with polariscope." 



In the comments upon the slide, Mr. C. M. Vorce says: "The slide 

 contributed by Pres. Lockwood contains crystals of almost exactly 

 the form of ammonio- phosphate of lime and magnesia from the urine 

 of mammals; the feathery form of the crystals indicates, under the 

 conditions stated, that other salts besides urates are present in the 

 fluid. 



" The uric acid crystals of lepidopterous larvae at about the time 

 of pupation can be obtained from the secretion of the uriniferous 

 tubes, which are large and easily recognized at that period. 



" By dissecting out the tubes under alcohol and putting them in 

 water on the slip, and tearing them apart, their contents dissolve in 

 the water; on removing the fragments and stirring the water with a 

 toothpick moistened with muriatic acid, a mass of crystals will be 

 deposited which polarize with remarkable brilliancy." 



Slide No. 6, prepared and contributed by Eugene A. Eau, of 

 Bethlehem, Pa., is of trichime spiralis muscularis; a clinical history 

 of the cases is given and the result of autopsies made upon the sub- 

 jects who had died of the disease. Excellent micro-photographs 

 accompany the description. 



ELEMENTARY DEPARTMENT. 



KUDIMENTS OF PRACTICAL EMBRYOLOGY.* 



W. p. MANTON. 



SECTION VI. 



LABELING — SLIDE CABINET. 



§ 15. Any kind of a label desired may be used. That which 

 I find most convenient, however, consists of rather thick white 

 card-board, cut half an inch wide by an inch long. On one of these 

 is printed the name of the microscopist, below which the place of 



♦Copyrighted 1888. 



