1899] MICROSCOPICAL JOURNAL. 17 



to lift the cover when the fluid expanded, as the cover-glass 

 would be able to spring- sufficiently to resist the pressure. 



Mr. Hinton said all those which he had seen of this kind 

 had an air bubble in them, but he did not think they were 

 any the worse for this ; no doubt it allowed of the expan- 

 sion and contraction of the fluid in the cell. 



The President thought they had had a practically useful 

 discussion. About thirty years ago he belonged to a small 

 microscopical society at Manchester, and the members 

 used to practice mounting objects ; bnt they got into very 

 considerable difficulties with regard to aqueous fluids. 

 Some few of their members, especially one man, however, 

 seemed to have no trouble, and specimens which he mount- 

 ed then were as good as ever at the present time. He 

 thought that personal equation came in very considerably 

 into the matter — one man failed whilst another seemed to 

 know exactly how to do it without knowing why. He 

 thought Mr. Morland had hit the right nail on the head in 

 saying that the cements sold under the same name were 

 not always of the same^composition, and therefore they 

 might succeed at one time and yet fail at another with ce- 

 ment of the same name, although purchased from the 

 very same place. He felt pretty certain that very much 

 depended upon the ability of the person who did the mount- 

 ing, as also upon the way in which the slides were mount- 

 ed, and to what temperature they were afterwards exposed . 



Microscopy by the General Practitioner. 



BY W. N. SHERMAN, M. D. 

 Merced, Cai,. 



No instrument yet devised by the ingenuity of man 

 equals the microscope in its universal application to 

 research in the broad domain of science, and its practi- 

 cal relation to medicine is well known. The greatest ad- 

 vances made in placing scientific medicine on its true 

 foundation date from the application of the microscope 

 to physiological investigations. The microscope alone re- 



