1893] MICROSCOPICAL JOURNAL. 279 



large, or too small ; experiment proves that a space three inches 

 and three-quarters in diameter approximates nearest to the im- 

 pression made on the mind, of a " field " as seen with a B eye- 

 l)iece, this circle may encompass magnifications under any 

 l)ower. A metal plate four inches and three-quarters square, 

 with an opening of the dimensions given, s'lould be procured, 

 this ascertained gauge will soon prove a necessity — placed on a 

 drawing block, a pencil swept round the circle and outside the 

 square gives the interior for the drawing and the line for back- 

 ing with India ink — these discs should be prepared before the 

 work is commenced, and the importance of this arrangement 

 will be easily understood. 



The Meeting at Madison, Wisconsin. 



The Sixteenth session of the American Microscopical Society 

 was arranged to commence two days before the A. A. A. S. meet- 

 ing at the University of Wisconsin. At both, the attendance was 

 small. About 15 new members were elected and four or five 

 papers got read. Those entered for publication were — 



A new clearer for collodion, by Pierre A. Fish. 



The simplification of laboratory methods, by Wm. C. Krauss. 



The effect of acid urine and solutions of chromic acid on red 

 blood corpuscles, by M. L. Holbrook, M. D. 



On sectioning fern prothallia, and other delicate tissues, by 

 Mason B. Thomas. 



Parasitism of the Broom rape on beech roots. Epiphegus 

 on Fagus, by Herman Shrenck. 



A contribution to the study of the Myelin degeneration of 

 pulmonary alveolar epithelium, by Veranus A. Moore, M. D. 



The study of reagents in micro-work, by V. A. Latham. 



Minute structure of certain aerotropic roots, by W. W. Rowlee. 



Points in the history of a new Distoma, by Henry B. Ward. 



The arrangement and structure of the muscles of the Lam- 

 prey (Petromyzon), by S. H. Gage. 



Sarcina ventriculi in medico-legal investigations of bh)od 

 stains, by W. N. Sherman, M. D. 



Progress in investigation of diatom structure. Some new 

 photomicrographs by T. H. Smith of London, by Jacob D, Cox. 



A spectroscopic study of colored inks. A metric study of 



