210 THE MINUTE ANATOMISTS 



sometimes give the clue to future discoveries. It is not 

 surprising therefore that a spider should furnish the 

 occasion for one of his most interesting letters, written, 

 we may remark, in his sixty-ninth year. 



He happened to begin with the microscopic examina- 

 tion of a spider caught in his house, and the first thing 

 which he remarked was the blood coursing through 

 the legs. The spider managed to escape, so Leeuwen- 

 hoek went on to examine the next spider which came to 

 hand, a garden-spider. He had remarked that when 

 dropping by its line from a height, a spider may often 

 be seen to pause, and support itself by grasping its line 

 with one of its hind feet. This led him to look carefully 

 at the structure of the foot. He found a pair of serrate 

 claws, and between them a smaller, non-serrate claw, 

 which he supposed to be that which grasped the line. 

 Next he examined the parts of the mouth. The poison- 

 fangs are well described and figured, the piercing 

 terminal joint, the double row of spines between which 

 the terminal joint folds up, and the minute orifice 

 of the poison-duct being all clearly shown. The four 

 pairs of eyes are drawn. He remarked that captive 

 spiders, when fairly matched in size, fight with great 

 determination, and that if the central part of the body 

 is wounded by the poison-fangs, the injury is mortal. 



We find here the first tolerable account of the 

 spinning apparatus of the garden-spider. Having fixed 

 a spider on its back, Leeuwenhoek with a pair of forceps 

 drew out a thread, noting that it was composed of 

 innumerable parallel filaments. At the extremity of the 

 abdomen he found five triangular valves meeting in 

 a point ; the uppermost (really the tip of the abdomen) 

 emitted no threads, but the other four (the spinners ; 

 there are actually six, but two of them are concealed) 



