54 



THE AMERICAN MONTHLY 



[March, 



194. Max Schultze. ZurKenntniss 

 der Leuchtorgane von Lanipy- 

 ris splendidula. x\rch. mi- 

 krosk. Anat. , i, 133. 

 M. Schulze und Rudnefi". Weitere 

 Mittheilungen ueber die Ein- 

 wirkung der Ueber-osmium- 

 saure auf thierische Gewebe, 

 I.e., p. 300. 

 In the first article, Schulze gives 

 the results of experiments with a new 

 reagent, O, O^, that later was named 

 perosmic acid. Substances easily 

 oxydized like oi'ganic tissues become 

 black or blue-black by treatment with 

 an aqueous solution of this acid, 

 showing a lower oxidation of the acid 

 or of the metal itself. F. E. Schulze, 

 in Rostock ascertained first that the 

 various tissue elements acted with 

 unequal reducing power on osmic 

 acid, and he sent a very dilute solu- 

 tion to Max, with request to test its 

 value in histological investigation. 

 On applying it to an examination of 

 the light producing organ of Lampy- 

 ris, it was found that the trachea 

 stained more readily than the other 

 elements, becoming black while the 

 others were only slightly colored: 

 But the staining took place onl}' in 

 living insects, and vanished on pres- 

 ei'vation. The application of oxvgen 

 gas to the organs made the staining 

 more permanent. The terminations 

 of the air tubes in other organs black- 

 ened readily. The staining of fats 

 and albumen is independent of life in 

 the tissues. In the second article, S. 

 and R. relate finlher experiences 

 with osmic acid. Making use of very 

 vs^eak solutions, i -^ 100 and i -i- 1000, 

 fat and milk globules were found to 

 blacken rapidly. The gray matter of 

 nerves stains most easily next to fats, 

 but the color is superficial and does 

 not penetrate deeply. When fresh 

 nerves are treated with osmic acid, 

 the vesicles do not become disorgan- 

 ized as usual. The axis-cylinder 

 stains very slightly or not at all. 

 Fibrous connective tissue and muscu- 

 lar substance stain very slowl}-, the 

 softer protoplasmic cells become 



dark. Cartilage, the cornea, and 

 similar tissues stain but little, also 

 spongy connective tissue like the 

 fibres of the retina. Striped muscle 

 becomes slowly brown, white blood 

 corpuscles, deep black, the red re- 

 main unaltered. The new reagent 

 is most important for the nerves, es- 

 peciallv in connection with carmine. 

 In plant tissues tannin material and 

 oil glands are colored, and more 

 slowly cell protoplasm, but not at 

 all starch sugar cellulose and chloro- 

 phyll. 



[T'o be co)iti)iiiedr\ 



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Cloud Vesicles. — It has been as- 

 sumed by some writers on physics 

 and meteorology that the minute va- 

 porous elements constituting clouds 

 are hollow vesicles — minute spheres 

 of vapor surrounding a central nu- 

 cleus of air. The microscopical ob- 

 servations of R. Assmann* on the 

 Brocken do not confirm these as- 

 sumptions. He found the smallest 

 particles in the upper cloud limit, to 

 have a diameter of 0.013 mm. The 

 diameter increased on descending 

 through the cloud until at the lower 

 part it was 0.033 iim^- The break- 

 ing of a hollovv^ vesicle upon a 

 plane surface would produce a w^ater 



* Zeitschr.f. Meteorologie,\\,\i. Abstr. m Zeitsch. 

 _/". Mikr., ii, 269. 



