| 766 General Notes. [ November, 
than an active movement due to their “ glutinosity.” How far 
_ these facts account for the connective tissue hyperplasia which 
accompanies varicose veins, the enlargement of the spleen which 
usually follows portal obstruction, etc., depends upon one’s ideas 
of pathogenesis. 
“A Handy Rule for use in Micrometry,’ by C. M. Vorce, of 
Cleveland, described very clearly the methods adopted by the 
author in making miscropical measurements. 
Professor Romyn Hitchcock, of New York, in a paper entitled, 
“A Standard Micrometer,” urged the adoption of a standard 
which should give some uniformity in micrometric work by dif 
ferent observers. Efforts to secure this end have been made, 
years ago, but they seem to have led to no results. We are now 
as far from a definite standard as ever, and the question can only 
be settled by a representative body like this, or by one convened 
for the special purpose. Not only accuracy but uniformity is es- 
sential, for convenience in reading and comparing observations. 
A fraction of an inch might seem the preferable unit of measure- 
ment to us in this country, but it can never become universal. 
The metric system is the only one that can ever become universal, 
and we should now adopt it even at some temporary sacrifice of 
convenience. 
Professor Rogers, whose facilities for accurate ruling have been 
greatly increased during the last few months, proposes to rule six 
scales, as nearly alike as possible, and donate five of them to the 
same number of microscopical societies, as standards, the socie- 
ties haviny first appointed a committee to examine, compare, and 
approve the scales. (Near the close of the Congress, resolutions 
were offered by Professor Hitchcock, and adopted, recommend- 
ing yds of a millimetre as our unit of micrometry, requesting 
microscopical societies to formally adopt this standard, an 
recommending to the favorable consideration of the societies, 
Professor W. A. Rogers plan for the acquisition and distribution 
of standard scales. This action was taken by the Congress with- 
out opportunity for discussion, and for the purpose of bringing 
the matter before the country for concerted action. It is possible 
that the unit suggested will need reconsideration, as one millime- 
tre might be more convenieut and more easily agreed upon than 
a nameless fraction).—(Zo de Continued.) 
ExcuanGes.—Lake Michigan diatoms, mounted or raw mate- 
rial, also diatoms of Northern Illinois, for good slides or material. 
B. W. Thomas, 132 La Salle street, Chicago, Illinois. 
Diatoms: Rhabdonema adriatica, Synedra ulna, splendens and 
superba, Tabellaria flocculosa, Fragilaria virescens, Isthmia ner- 
vosa, diatomaceous earths and other unmounted material, for 
named diatoms or other good mounted objects. M. A. Booth, 
Longmeadow, Mass. a ? 
ides of named diatoms, also peristome of Funaria hygro- 
