Cxi GENERAL SUMMARY OF SCIENTIFIC AND 



inch. He states, with true English pertinacity, that though 

 the Committee of the British Association have from time to 

 time recommended the French meter for the unit, En- 

 glishmen will not become Frenchmen, and adopt a unit that 

 theoretically holds good only when measured across the ter- 

 ritory of the French republic. 



The artificial production of silica films, with a view of 

 adding to our knowledge of high power definition, and pos- 

 sibly throwing light upon questions of crystallization and 

 organization, has received a new impulse in Mr. Slack's dis- 

 covery that the gas escaping from a heated mixture of pow- 

 dered glass, powdered fluor-spar, and sulphuric acid (and 

 which, when received into pure water, deposits the silica 

 suddenly and violently in amorphous particles), gives deli- 

 cate films with definite forms, exhibiting remarkable regu- 

 larity of size and arrangement when conducted through a 

 mixture of glycerin and water. Some of the films produce 

 the beautiful polychromatic effects so often noticed in beaded 

 diatoms and scales. 



In the August number of the Monthly MicroscopicalJour- 

 nal is a paper by Dr. George D. Beatty, of Baltimore, re- 

 printed from the Cincinnati Medical JVeics, on "Double 

 Staining of Wood and other Vegetable Substances." The 

 author states that benzol fixes the anilines when used in 

 staining tissues, and also renders them transparent. The 

 double staining the spiral vessels, e. g., of leaves red, and the 

 other parts purple or blue, is obtained by immersing the 

 section for five or ten minutes in an alcoholic solution of 

 roseine (Magenta), and afterward in Nicholson's soluble 

 pure blue for thirty or ninety seconds, rarely longer, with 

 examination during this time to decide upon the proper in- 

 stant for fixation by immersing in the benzol. We com- 

 mend the article to those interested in this subject. 



Blood. In a paper read at a late meeting of the Zoolog- 

 ical Society, Professor Gulliver stated that in the mammalia 

 the largest red corpuscles of the blood are those of the two 

 elephants, the two-toed sloth, and the walrus. In the human 

 subject the corpuscles are exceeded in size by those of only 

 eight or nine exotic mammalia, and not equaled in size by 

 the corpuscles of any British animals of the class. And this 

 fact, independently of its physiological interest, may prove 



