FRAGMENTS OF SCIENCE. 



427 



than 500 writers ; and about 700 entomo- 

 logical papers have appeared since then 

 from the agricultural experiment stations. 

 Hence, the author estimates the bulk of 

 writings on insects available now at between 

 12,000 and 15,000 volumes; and this does 

 not include the recent literature of apicul- 

 ture. On a similar basis of calculation it is 

 estimated that there are between twelve and 

 fifteen hundred people now living whose 

 works on insects are of such a character as 

 to be noticed in the standard annual books 

 of record. Besides these are the writers on 

 bees, and the very large number of collectors 

 of insects who rarely write on the subject. 

 The number of species of described insects, 

 excluding arachnids and myriapods, is esti- 

 mated at 250,000 ; and it may be that, the 

 world over, there are 10,000,000 species in 

 all. Thus only one in forty of probably exist- 

 ing species is known — a fact that seems to 

 throw grave doubt on much of our classifica- 

 tion and characterization of genera. About 

 1,200 new genera and subgenera are added 

 every year. " That the entomologists of the 

 world have ample material with which to 

 work, and that there is no alarming prospect 

 in the immediate future of exhaustion of 

 the field, is strikingly apparent." Dr. David 

 Sharp has recently computed that in the 

 matter of bulk insects probably outrank all 

 other animals together, their small size being 

 more than counterbalanced by the vast num- 

 ber of species and enormous multitude of 

 individuals. 



Economical Tses of Bacteria. — Prof. H. 

 Marshall Ward, in his presidential address, 

 which was read in his absence before the 

 Botanical Section of the British Association, 

 dwelt at considerable length on the many 

 industrial processes which depend more or 

 less for their success on bacterial fermenta- 

 tions. The subject is young, he says, but 

 the little that has been discovered makes it 

 imperative that we should go on, for the re- 

 sults are of immense importance to science, 

 and open up vistas of practical application 

 which are already taken advantage of in 

 commerce. A bacillus has been discovered 

 by Alvarez which converts a sterilized decoc- 

 tion of indigo plant into indigo sugar and 

 indigo white, the latter then oxidizing to 

 form the valuable blue dye, whereas the 



sterile decoction itself, even in the presence 

 of oxygen, forms no indigo. Certain stages 

 in the preparation of tobacco leaves and of 

 tea depend on a carefully regulated fermen- 

 tation, which must be stopped at the right 

 moment, or the product is impaired or even 

 ruined. While in flax and hemp the best 

 fibers are separated by steeping in water till 

 the middle lamella is destroyed, not every 

 water is suitable for the process, but only 

 that containing a particular bacillus, which 

 destroys the pectin compounds of the lamella 

 and leaves the cellulose. A process depend- 

 ing on this fact has been patented in the 

 United States. The steeping of skins in water 

 preparatory to tanning involves bacterial ac- 

 tion for removal of the hair and epidermal 

 coverings ; and the swelling of the limed 

 skins is a fermentation process. Hay and 

 ensilage have to go through fermentations in- 

 volving bacterial action. The various flavors 

 of butter and cheese are each pi-oduced by 

 special bacteria, and the cultivation of them 

 has become a considerable business, so that 

 the production of whatever flavor may be 

 desired has become a matter of reasonable 

 certainty. 



Areca and its Properties. — The areca 

 nut, a favorite stimulant of the many millions 

 of people living in the East Indies and beyond, 

 is the fruit of a tree, the Areca catechu, 

 which, as described by M. Ernest Martin, fol- 

 lowing Chinese authors, has a trunk like that 

 of the bamboo, straight and without branches, 

 jointed in the upper part, with leaves like 

 those of millet or sugar cane, under which are 

 spathes containing fruits about as large as 

 plums and protected by thorns. These nuts 

 are edible. The bark of the tree is like that 

 of the Paulownia ; and it is on the whole 

 very like the cocoa palm. It is regarded as 

 one of the handsomest ornaments of the 

 woods of the southern part of the extreme 

 East. The nut is extensively used as a stimu- 

 lant and as a remedy. It forms the basis of 

 a preparation, with betel and lime, which is 

 made to be chewed. After it has been used 

 for a little while the teeth begin to assume a 

 dark yellow or even blackish hue, from which 

 the Chinese say that the Cochin-Chinese, 

 Annamites, Cambodians, etc., tattoo their 

 teeth. The effect sought in chewing areca 

 is an excitation which, affecting the sali- 



