258 THE AMERICAN MONTHLY [November, 



English Approval. — Nature, for July 18, has a very complimen- 

 tary notice of the organization and work of the Marine Biological 

 Laboratory at Woods Holl, in which American biologists are cordially 

 congratulated upon the inauguration of so ideal a scheme as this is con- 

 sidered to be. 



Nucleus Division. — Mr. Douglas H. Campbell contributes to the 

 Botanical Gazette for August a brief article describing an easy method 

 of observing this interesting process in the pollen mother cells of Allium 

 canadense and Podophyllum peltatum. kt Young buds must be used, in 

 Allium about 2 mm. in length; in Podophyllum, buds were gathered as 

 soon as the plants appeared above ground. In the former case the young 

 anthers were crushed carefully in a drop of acetic acid and water (^ acetic 

 acid and \ distilled water). With Podophyllum, cross-sections of the 

 whole bud were made, and the sections of the anthei _ s teased out in the 

 same solution as in the case of the Allium. The pollen mother cells 

 are at once recognizable by their thick colorless walls, and it is easy to 

 tell with a low power whether or not the desired division stages are 

 present. If this is the case they may be stained with acetic methyl- 

 green, or, better, gentian-violet. In preparing the latter the best results 

 were had by first mixing two parts of distilled water and one of acetic 

 acid. To this mixture a sufficient quantity of saturated alcoholic solu- 

 tion of gentian-violet is added to give it a deep violet color. If a small 

 drop of this mixture is now added to the preparation containing the 

 pollen cells, the nuclei will be almost instantly colored a deep blue- 

 purple, while the protoplasm remains colorless and uncontracted. The 

 coloring fluid may now be carefully removed with blotting-paper, 

 * * * and the preparation mounted in dilute glycerine, which must 

 be added very gradually to prevent contraction of the protoplasm." 



A New Yeast. — Dr. W. Zopf, of Berlin, is reported to have dis- 

 covered a new species of Saccharotnyces , to which he has given the 

 specific name hansenii, in honor of the distinguished botanist, Dr. 

 Hansen, of the Erlangen Botanical Institute. This yeast differs from 

 the common yeast 6\ cerevisice in that it produces oxalic acid instead 

 of alcohol from the sugars of fruits, vegetables, and milk. It is said 

 to produce ascospores similar to S. cerevisice but in smaller numbers. 



Artificial Silk. — Visitors at the Paris Exposition report an exhibit 

 of rare interest illustrating the progressive spirit of modern invention 

 and the value of scientific discovery to practical industry. This is 

 nothing less than the process of making artificial silk. The process 

 consists in reducing ordinary cellulose, as wood fibre or cotton, to py- 

 roxyline by treating it with sulphuric and nitric acids. This product, 

 dissolved in a mixture of alcohol and ether, is familiarly known as col- 

 lodion. The pi'ocess of manufacture of the fibre consists in forcing 

 this liquid solution through very fine tubes into water, which hardens 

 it at once, forming a flexible fibre. In order to render this uninflam- 

 able, it is treated by a secret process, after which it is colored any color 

 desired and woven into fabric. This silk is said to compare favorably 

 with natural silk both in brilliancy and durability. The numerous 

 diseases which have rendered silk culture so difficult will greatly in- 

 crease the importance of this enterprise if it should prove practicable. 



