VOL. XXII.] PHILOSOPHICAL TRANSACTIONS. 587 



was expected ; for in a very little time the patient fell into a most violent colic, 

 from no other occasion, that he could discover, than his late illness putting on 

 a new form, and the matter settling on the bowels. This colic was in good 

 measure overcome by purging medicines ; but a disposition to it still remains ; 

 for he has ever since been often troubled with it, as also with a spitting of 

 blood, on the least excess of cold or motion. In short, he has, ever since the 

 stoppage of that first haemorrhage, been weak, sickly, of a faint look ; much 

 impaired as to health, in comparison to what he enjoyed during the time of its 

 periodical returns ; which proves, that when nature has chosen, and for some 

 length of time exercised, new and extraordinary methods of economy, she 

 seems to be as fond of their continuance, as at other times, and in her most 

 regular state, she is of that which is her most usual and ordinary course. 



A further observation may be made from this, and such like monthly 

 haemorrhages, in men ; whether by the thumb, or per penem, or any other part 

 of the body. For these evacuations, being analogous to the menses in women, 

 confute the opinion of all such as derive that discharge from a fermentum 

 uterinum. For how can we think the menses come from such a local ferment ; 

 when a discharge, in all respects equivalent to them, takes place, where no such 

 ferment is, or can be supposed. 



Concerning Spiders, their fFay of Killing their Prey, Spinning their Webs, Ge- 

 neration, ^c. By M. Leuivenhoech, F. R. S. N° 2/2, p. 867. 



About the latter end of February, I caught a black spider, and viewing it with 

 my microscopes, I observed that his body and legs were covered with a great 

 number of hairs, that stood as thick as the bristles on a hog's back. Though 

 hairy, yet the legs were so clear, that I could easily perceive the circulation of 

 the blood in several veins which were not a hair's breadth distance from each 

 other ; and afterwards I saw other fine blood-vessels, that were not the tenth 

 part of a hair's breadth distant from each other. With the strictest observation 

 I could not discover the course of the arterial blood; but I could see, even in 

 the smallest of the legs, three vessels together that conveyed the blood directly 

 to the heart. Notwithstanding that this animal is by the ancients esteemed a 

 bloodless insect, because they could discover no red matter in the body when 

 they killed or crushed it to pieces, yet I plainly perceived some particles of 

 blood, which according to all appearance were spherical, circulating in a liquid 

 matter. But these particles of blood were extremely small, in comparison of 

 those globules that are discovered in larger animals, for I saw a space of three 

 hairs' breadth, where no particles of blood circulated ; and the blood was ex- 

 pelled with great swiftness. I have viewed this spider a great many times, and 



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