116 THE AMERICAN MONTHLY [June, 



softened to make a number of sections. The teeth are taken from the acid sokition, 

 washed in distilled water, and then placed in a solution of gum-arabic for several hours. 

 They are then put into a solution of alcohol to take out the water. Paraffine and lard 

 are melted together and poured into a convenient mould. When the former is clouded 

 in the process of cooling, the tissue, which has its outer surface dried as much as pos- 

 sible with bibulous paper, is placed in it and allowed to cool. Sections are now cut 

 from it. The microtome which I use has an advantage over others, the tissue and 

 knife both being under fluid when the sections are cut. The sections float off in the 

 fluid and remain there until used. I cut until the calcified tissue is reached. The 

 method has cost me a number of fine knives, for each cutting ruins an edge ; but I have 

 the satisfaction of working as near life as we can with our present knowledge. After 

 cutting the sections they are placed in distilled water for a few minutes to dissolve out 

 the gum, and are then mounted in Markoe's glycerin jelly. The difference in the ap- 

 pearance of the tissue prepared by this method is marked.' 



o 



Washington, D. C. — E. A. Balloch, Secy. 



Feb'y 28, 1888. — The 73d meeting. Prof. A. N. Skinner read a paper on standards 

 of length, giving a full account of the measures of length in use at various times, and 

 the origin of the same. 



March ij, 1888. — The 74th meeting. Dr. Cooper Curtice gave a full account of the 

 life history of Taenia soliinn, illustrating his paper largely by the use of specimens and 

 diagrams. Specimens of T. pectinata and other tape-worms were also shown. Dr. 

 Curtice will gladly identify specimens of tape-worm which may be sent him at the De- 

 partment of Agriculture, for the sake of the specimens. 



March 2"/ , 1888. — The 75th meeting was held at the residence of Dr. E. P. Rowland 

 for the purpose of giving him opportunity to show his apparatus for projection. Both 

 microscopic slides and lantern views were projected with great success, the light being 

 furnished chiefly by the electric arc light. 



April TO, /88S. — The 76th meeting. Dr. J. M. Lamb remarked on serial section- 

 cutting. I have tried all the various mixtures recommended as imbedding-masses for 

 serial section-cutting, and have at last settled down upon paraffine, pure and simple, 

 as the most satisfactory. A proper consistency may be obtained by using paraffines 

 of different degrees of hardness. I have also found that a proper consistency may be 

 obtained by varying the temperature of the room, and in some cases where the paraf- 

 fine was too hard I have succeeded by heating the point of the microtome knife gently 

 by the flame of a spirit lamp, and cutting with the heel. Where all these fail, I imbed 

 the mass anew and try again. 



Dr. Blackburn testified to the efficiency of paraffine as an imbedding mass for this 

 purpose. 



Leavenworth Microscopical Society. — W. D. Bidwell, Secy. 

 A/arch ig, /888. — This monthly meeting, held at the ' Delmonico ' parlors, was of 

 the nature of a soiree, friends of the members being present by invitation. Dr. W. D. 

 Bidwell read a paper on the value of the microscope in the medical profession. Prof. 

 W. D. Lighten spoke of the construction and use of the immersion lens. Drs. O. C. 

 McNary and C. R. Ciarpenter made remarks on crystallization. Nine microscopes and 

 fifty slides were exhibited and explained to the visitors. The next meeting to be held 

 at Prof. Lighton's residence; subject, 'blood.' 



Louisville Microscopical Club. — Simon Flexner, Secy. 



Tuesday, March jo, 1888. — The Club voted to go into morning session, when a 

 number of objectives, among thein a jV i^- first-class Bausch & Lomb, were tested. 

 The yV in. was thoroughly tested on Amphiplcitra, including the difficult one from Floyd 

 Co., Ind. It proved a very satisfactory lens. 



Dr. Charles Mitchell, of Nashville, Tenn., was elected an honorary member of the 

 Club. The doctor has just received a new -^ in. 130° B. A. from Spencer. It is a 

 beautiful working lens, and readily spoke for itself. 



Contributions were received from Miss M. A. Booth, Longmeadow, Mass., nine 

 slides of recent and fossil diatoms beautifully prepared, and from Dr. John Sloan, New 

 Albany, Ind., 24 slides of named diatoms prepared in his usual excellent manner. 



