( 224 ) 



driven from A to B, from the heart, and took its courfe from B to 



C, in C, being emptied into a vein, it returned back, from C to 



D, tovi^ards the heart: the other fmall artery, B F, took a courfe out 

 of my fight at F. This circulation gradually decreafed till, at length, 

 I could not perceive any motion in the veflds ABC and B F. 



Thefe obfervations I alfo purfued in feveral other forts of fifh, and 

 in all of them the circulation was very apparent, particularly the 

 Flounder, in the tail fin of which I faw fuch multitudes of minute 

 blood-veflels, that I may fay there is not a fpace in that fin, fo fmall 

 as a grain of fand, which does not contain a veflel, either conveying 

 the blood from the heart, or bringing it back towards the heart. 

 This fifli, called the Flounder, is one of the beft adapted to view the 

 circulation of the blood, becaufe it lies quiet a long time, and alfo 

 \\ ill live a long time out of the water. 



With regard to the infiruments I have defcribed, they might, I 

 doubt not, be made more perfect and convenient ; for I myfelf was 

 never infi:ru6led in the working in brafs and iron, otherwife than by 

 obfervation of workmen in the making and ufing their tools ; by 

 which means, however, I have been enabled (rather in a rude way) 

 to make thefe infiruments fufiicient to anfwer all my purpofes. 



Addition, by the Translator. 



AS the reader may have a defire to know of what nature were the Mi- 

 •crofcopes by which Mr. Leeuwenhoek made the wonderfal difcoveries, wliicli 

 are the fubjeft of his works, the Trandator has thought proper to introduce, 

 in this place, the bed account of them he has been able to colIeO. 



Mr. Henry Baker, in his IntroduQion to the ufeof the Microfcope, has 

 thefe words : * 



" The famous Microfcopes of Mr. Leeuwenhoek are the mofl fimple pof- 

 " fible, being only a fmgle lens fct between two plates of filver, perforated 

 *' with a fmall hole, with a moveable pin before it to place the objed on, and 



• Wicrofcopc made Eafy, p. 7. aud 8. Ed. 1711. 



