342 PROCEEDINGS OF THE ACADEMY OF 



this exhibit cannot compare favorably with those of other like 

 periods, it must, I think, be admitted that evidence is thereby 

 afforded of an earnest determination to keep alive some interest 

 in the study of microscopy. 



Valuable donations have been from time to time received from 

 Dr. J. J.Woodward, of the Surgeon-General's Office, at Washing- 

 ton, consisting of specimens of his admirable micro-photographs 

 of histological preparations, test objects from the Diatomaceae, 

 &c. &c. 



Among the more important contributions laid before the de- 

 partment may be mentioned one from Dr. James Tj'son, on a 

 method of demonstrating the reversal of light and shade oc- 

 curring in the red blood-corpuscles under microscopical examina- 

 tion, wiiich was subsequently printed in the Philadelphia Medical 

 Times. One from Dr. J. H. McQuillen, upon a remarkable ex- 

 ample of h3'pertrophy of the root of a tooth, the specimen being 

 first exhibited to the members in its natural state, and its con. 

 struction being afterwards demonstrated b\^ carefully prepared 

 and mounted sections. Another from the same gentleman on im- 

 perfections in the enamel of teeth, producing microscopical fis- 

 sures which constituted predisposing causes of caries, his remarks 

 lieing published in the Medical Times and Dental Cosmos, and 

 subsequently reprinted in the London Microscopical Journal. An 

 interesting contribution (also illustrated by specimens) upon in- 

 termittent hfematuria, from Dr. James Tyson, which likewise ap- 

 peared in the Medical Times, and was republished by various 

 medical periodicals. One from Dr. Tyson, on the existence of 

 true Haversian canals in hypertrophied cementum. Communica- 

 tions from Dr. Tj'son and Dr. Richardson in regard to the use of 

 acetate of potash solution as a preservative fluid for microscopical 

 specimens, and one from the latter observer, on the Detection of 

 Pulmonary Elastic Tissue in the Sputum of Phthisis. 



In conclusion, I would, unless we determine to abandon our 

 efforts, respectfully' urge upon my fellow-members the adoption 

 of the proposed change in our existing arrangement for holding 

 the meetings of the Department, in the hope that by reducing the 

 frequency of our meetings the diminished number of earnest stu- 

 dents of microscopy who remain will be able to present in rota, 

 tion, according to a systematic plan, on each stated meeting, some 

 written or oral communication, illustrated by specimens, which 



[April 9, 



