302 The Microscopi:. 



of Washington, D. C. This was to a considerable extent ex- 

 planatory of the things, microscopical, tliat our visitors were 

 expected to see. It is pretty generally known that Washington 

 is a centre of scientific work, but probably very few people out- 

 side of the city know that over eight hundred names are on the 

 rolls of the different scientific societies of the city and that among 

 these investigators the use of the microscope holds a prominent 

 place. Among the objects in the Army Medical Museum of 

 particular interest to lovers of this instrument, are two cases 

 containing specimens of microscopes illustrating the progressive 

 improvement in its construction from the earliest efforts to the 

 present time. A few of these are models constructed to order, 

 but many of them are the actual instruments that were used. 

 The work now being done in the museum consists largely in the 

 production of a complete series of sections of the human 

 embryo, illustrating the progressive growth of each month by a 

 complete set. Many of these slides must necessarily be of large 

 size, and to do this work properly a very large section cutter 

 has been procured. 



The Bureau of Animal Industry is just moving its quarters 

 from the old inconvenient rooms under the roof of the old de- 

 partment building to a new home all for itself, in which bacteri- 

 ological investigation will be carried on with a thoroughness not 

 to be excelled anywhere. The transfer being incomplete, all of 

 the rooms were not in working order, but enough was seen to 

 convey a clear idea of the way the work is done. 



In the Geological Survey the piincipal microscopical business 

 is the preparation and examination of rock sections by the mi- 

 croscope. The grinding of the sections is usually a tedious 

 operation, but several men are here employed, with the aid of a 

 small steam engine, and the work is done with comparative 

 rapidity. Several of the assistants in this department have 

 worked with Rosenbusch, especially Mr J. S. Miller, and one of 

 them, Mr Iddings, has translated Rosenbusch's principal work, 

 under the name of " The Microscopical Ph^^siography of Min- 

 erals and Rocks," and which is now our best text book on this 

 subject in English. 



On Tuesday evening, Dr Frank L. James, of St. Louis, the 

 President, delivered the annual address in the parlor of the 

 First Congregational Church, which the trustees kindly granted 



