52 



HARDWICKE'S SCIENCE-GOSSIP. 



has a vigorous style, and such akeeu eye for natural ' 

 phenomena, especially of a geological and physical 

 geographical character, that his delineations are 

 graphically impressed on the reader's mind. And 

 when we remember that the country thus delineated 

 is the Himalayan mountains to the table-land of 

 Thibet, those who have not read this book will 

 understand how thoroughly interesting it must be. 

 Travellers like Mr. Wilson do more than simply 

 interest us ; they contribute materially to natural 

 science by so vividly describing natural scenery 

 which few can ever behold. We heartily commend 

 this volume to our readers. 



A great many books have been issued since the 

 Arctic expedition left England concerning the 

 countries it has gone to explore. None of them, 

 however, come up to "The Arctic World," pub- 

 lished by T. Nelson & Sons, London. It is a large 

 qmrto volume, charmingly bound in crimson and 

 gold, and profusely illustrated by some of the best 

 full-page and other woodcuts we have seen since 

 those of Wolf. The letterpress is of a large type, 

 and agreeable to the eyes ; and the matter is well 

 written, although the chief Arctic travellers are 

 largely laid under contribution. The plants, animals, 

 and natural phenomena of the Arctic regions are 

 described and figured in a very truthful style. 

 Those who cannot go to these high latitudes must 

 do the next, best thing — get this attractive work. 



THE MICROSCOPE AND MICROSCOPIC 

 WORK. 



No. Ill— By F. Kittou. 



¥*N our last paper we gave a short resume of some 

 -*- of Leeuwenhoek's labours with the microscope. 

 In the present paper we propose to continue our 

 sketch of his studies with that instrument. Space 

 will not allow of more than short excerpts, and 

 these we shall make from the essays on the Spider 

 and Silkworm, as being the most interesting. Those 

 of our readers who have paid any attention to the 

 former animals will, perhaps, be somewhat surprised 

 that he overlooked those very extraordinary organs 

 the male palpi. With this exception Leeuwenhoek 

 seems to have had a very fair acquaintance with 

 the structure of this " animal." He says :—" I 

 have often seen the spiders, when dropping or falling, 

 as it seemed, from a tree, stop or support themselves 

 in midway by the help of one of their hind feet, 

 which they continually apply to the thread as they 

 open it. These feet are each of them furnished 

 with three nails or claws, standing separate or 

 apart from each other. Two of these claws are at 

 the extremity of the foot, and each of them is 

 formed with teeth, or notched like the cuts in a saw, 

 growing narrower towards the bottom; and with 

 these they are enabled to hold fast the thread, in 



like manner as the pulley or wheel used by clock- 

 makers in their thirty-hour clocks is contrived to 

 lay hold of the clock-line by means of the groove 

 being also narrow at bottom. For the more per- 

 fectly understanding this formation, 1 caused the 

 following figure to be drawn." 



The illustration is very good, and although not 

 quite accurate, gives a good idea of what we now call 

 the " combs." The general accuracy of Leeuwen- 

 hoek's figures is the more surprising, as he does not 

 seem ever to have prepared them in any way ; and 

 doubtless the use of caustic potash, &c, for the 

 purpose of bleaching, was entirely unknown to him. 



Fig. 25. Claw of Spider (from Leeuwenhoek). 



These instruments are now supposed to be used 

 for the purpose of cleaniug the web, but no doubt 

 they serve for both purposes. 



To Leeuwenhoek belongs the credit of the dis- 

 covery of the poison-fangs of the spider. The 

 existence of these organs as the means of conveying 

 a poison was questioned as recently as 1867, when 

 several correspondents of Science-Gossip argued 

 for and against their existence. Mr. R. Beck, in a 

 paper on this subject, remarks that Leeuwenhoek 

 had discovered the nature of the fangs, and gives a 

 copy of his figure, which we here reproduce. As 

 Leeuwenhoek's observations are of considerable in- 

 terest, I transcribe them : — " I have often heard it 

 said that the spider has a sting, with which it is 

 also reported it can kill a toad ; but no one could 

 tell me in what part of the body this sting was 

 placed ; therefore I concluded that, if there was 

 one, it must be in the posterior or hind part, as in 

 other animals and insects; but on examination 1 

 found this opinion to be groundless. The spider is, 

 however, provided with two organs or weapons 

 answering every purpose of a sting, which are 

 placed in front of the head, just below the eyes, and, 

 when not in use, they lie between the two shorter 

 feet. These weapons, or instruments of offence. 



