THE MICROSCOPE. 53 



WE present our readers with a fine lithograph of uric acid crys- 

 tals. The crystals were drawn by Mrs. Stowell from the 

 actual specimens, and engraved by the Detroit Lithographic Co. 

 It forms one of the four plates of uric acid which will appear in our 

 new work, " Microscopical Diagnosis." Mrs. Stowell has drawn 

 over thirty figures of the urinary deposits, all from specimens pre- 

 pared especially for her by a specialist employed in teaching this 

 branch for twenty years. As original figures, we do not hesitate to 

 declare them to be the best executed and most natural in appear- 

 ance of any in existence. 



" Microscopical Diagnosis " will contcin also a large part of the 

 original work that Mrs. Stowell has completed during the past 

 three years. This portion is beautifully illustrated with the finest 

 wook-cuts. Part i, of the work, is occupied by a thorough descrip- 

 tion of the microscope and methods of work, together with several 

 chapters treating of all microscopical facts appertaining to medical 

 diagnosis. 



Arrangements have just been completed with Mr. Walmsley, 

 and his valuable articles on mounting, which our readers have en- 

 joyed, will appear in Part 3 of this work; the concluding chapters 

 of this subject will be given there also. The book is a large 8vo and 

 will contain possibly 300 pages. Especial terms are offered to old 

 and new subscribers. See our advertising page. The book will be 

 ready for the market by the ist of June. 



WE are in receipt of an announcement from Jas. W. Queen & 

 Co., calling our attention to some recent additions to their 

 stock. Their "college microscope" is furnished with two eye pieces, 

 two objectives, condenser on stand, and mahogany case for $45.00. 

 They also offer the celebrated objectives of Zeiss. We notice the 

 receipt of a new lot of Prof. Abbe's test plates, for testing objectives 

 in regard to spherical and chromatic aberration, $2.50. 



We have been familiar with the goods of this firm for a number 

 of years, and we are glad to be able to ask you to look on advertis- 

 ing page I and then send for one of their catalogues. 



MR. BREARLEY, of Detroit, has given us some slips of paper, 

 upon each of which is printed a synopsis of one of the Dia- 

 tomacese. Each Diatom is illustrated and a brief description given 



