36 



KNOWLEDGE, 



[Februabt, 1002. 



Astronomical. — The discovery by Dr. Stewart of a 

 new minor planet of more than average interest is 

 announced bv Prof. E. C. Pickering. A photograph, taken 

 on August 14th last, revealed the presence of the ])lanet, 

 and later jihotographs showed that its daily motion was 

 uucomtnonly large. A preliminary computation indicated 

 that the ])Ianet was nearer to the sun than any other of its 

 class at present known. Prof. Newcomb finds that the 

 period is 413 years, the mean distance 2'.57 that of the 

 sun, the eccentricity 0'377, and the inclination 18' 38'. 

 The new planet is now moving rapidly northwards, having 

 crossed the equator about the 20th of January. Mr. S. B. 

 Gaythorpe has drawu attention to the fact that the 

 eccentricity of the orbit of the new jjlanet is slightly less 



than that of iEthra — M^32\ 



Continxied investigations have established the reality 

 of the changes in position of parts of the 

 luminosity of the nebula surrounding Nova Persei, and 

 explanations which aim at avoiding the seemingly 

 impossible velocities which an actual translation of matter 

 would require, are being put forward. Prof. Kapteyn and 

 Mr. W. E. Wilson have independently suggested that the 

 light of the nebula is reflected from the Nova, and that the 

 apparent motion is nothing more than the progression of 

 the light rays to nebulous or meteoritie; matter situated at 

 gradually increasing distances. On account of the vast 

 distances of the nebulous matter from the Nova itself, it 

 is supposed that the light of the original outburst may 

 have taken months to reach it, so that the nebulosity did 

 not appear until the star bad greatly decreased in 

 brilliancy. Sir Norman Lockyer has suggested that the 

 luminosity of the nebula is produced by collisions of 

 meteoritic matter, and that it is the loci of disturbances 

 which are varying in position. A difficulty which presents 

 itself is that the most prominent part of the nebula 

 retained practically the same form during its movement. 

 —A. F. 



Botanical. — Monsieur Laurent has an interesting 

 paper in the Cnmptes Bendus de VAcadhnie des Sciences, 

 Paris, of December 2nd, 1901, respecting the poisonous 

 action of the mistletoe on certain varieties of pear, shown 

 by the sudden dying off of the young branches during the 

 heat of the summer. At the point of contact of berries, 

 seeds, or young j)lants of the parasite with the bark of 

 the pear tree, and even for several centimetres around it, 

 the cortical parenchyma is killed and contracted, the 

 vessels become choked up with gum, which interferes with 

 the passage of the sap, in consequence of which the 

 neighbouring leaves wither, and ultimately the branch 

 dies. A single young plant of the mistletoe was found 

 sufficient to kill a branch several years old. Though the 

 poisonous principle resides in the pulp of the berries and 

 in the seeds, it is most abundant in the young plants. 

 The curious fact has been noticed that the mistletoe will 

 not establish itself on some varieties of pear. This is 

 shown to be due to the early death of the cortical tissue 

 at the points where the seeds of the parasite germinate, 



and the younf plants die before the haustcria can pene- 

 trate the bark of the host. Monsieur J. Clialon has 

 oliserved that the mistletoe has a similar poisonous action 

 on Sj)artiiim jtniceiim and Fieiig elastica. 



Professor Matouschek, writing in the Devtschp Bolan- 

 ische Monafsschrift of December, 1901, mentions that an 

 exceedingly tine female specimen of the yew growing in 

 the village of Ungersdorf, Moravia, does not fail to produce 

 its well-known fruits, though no male plant grows in the 

 vicinity. On investigation he found that the pollen, 

 which is conveyed to the female flowers by the wind, must 

 have travelled upwards of five kilometres, the distance 

 from Gaisdorf and Loipnilc, where the nearest male 

 specimens are met with. 



It i.s well known that certain plants or parts f)f ])lants 

 are difficult to dry satisfactorily. For instance, Orohus 

 niger and many Scrophulariaceie (Pedicularis, Melam- 

 pyrum, etc.), which turn black during the process of 

 drying, and flowers, which often lose their characteristic 

 colours. Professor Rostowzew describes in Flora, 1901. 

 Heft 3, two methods of drying botanical specimens, which 

 have given excellent results. In that recommended for 

 general use, pads of absorbent cotton about half an inch 

 thick, and each wvajiped in a sheet of tissue paper, are 

 substituted for the ordinary drying material. The other 

 method is termed drying plants on a metal cylinder, and 

 is especially applicable to succulent specimens. Its salient 

 features are a hollow metal cylinder, freely perforated at 

 the sides, and covered at the top with a metal lid. The 

 cylinder is tightly covered with a liuen cloth on which the 

 specimens, placed between layers of drying paper, are 

 fastened. It is then stood on a tripod and a lamp applied 

 at the bottom. The heat from the lamp will quickly expel 

 the moisture from the specimens. — S. A. S. 



Zoological.-— Some months ago an article appeared in 

 our columns on the manner in which Arctic mammals 

 turn white. Important additional information with 

 regard to the manner in which hair bleaches is afforded 

 by a communication from Mr. E. Metchnikoff, recently 

 published in the Proceedings of the Royal Society. It is 

 there stated that the all-devouring cells known as 

 j)hagocytes are the cause of the mischief. These cells, 

 which frequently have am£eba-like processes, are developed 

 in the central or medullary part of the hair, whence they 

 make their way into the outer or cortical layer, where they 

 absorb and thus destroy the pigment -granules. Numbers 

 of these phagocytes may be seen in hair which is com- 

 mencing to turn white. 



" The part played by phagocytes," writes the author, 

 " in the whitening of hair explains many phenomena 

 observed long ago, but not as yet sufficiently uuderstood." 

 Thus the phenomenon of hair turning white in a single 

 night, or in a few days, may be explained by the increased 

 activity of the phagocytes, which i-emove the pigment 

 within an abnormally short period. 



It appears from a communication published some time 

 ago iu our American contemporary, Science, that the 

 California Fish Commission ordered the destruction of 

 10,000 sea-lions on the coast of that State, on account of 

 the damage they do to the salmon fishery. It was ex- 

 pressly stated that the seals were not to be exterminated, 

 but only a third of their number destroyed. Dr. C. H. 

 Merriain points out, however, that 10,000, in place of 

 rej)resenting a third of the number of these animals, 

 probably exceeds the total. And he further points out 

 that these sea-lions feed almost (if not quite) entirely on 

 cuttles and squids, and do not touch fish. As Dr. 

 Merriam observes, the fact that sea-lions in captivity will 



