188 Dv. ^furgia's Outlines of a Philosophical 



and susceptibility lo motion ; or in other words, their own 

 fluidity to crasser or grosser combinations of matter, — as in 

 the case of the blood more especially ; for we regard it as an 

 axiom, that for every natural effect there must be a natural 

 efficient cause. 



Seeing then that in order to the blood's fulfilling certain 

 purposes and designs, — for we fear not to say that the best pur- 

 poses and the wisest designs are discernible in the formation 

 and mode of existence of every living thing, — it must enjoy 

 fluidity in a very eminent degree ; it must admit of so subtile 

 a division without a destruction of its nature, as will enable it 

 to penetrate into those minute channels and secret recesses 

 where the human eye-sight is eluded, and where those deli- 

 cate manipulations and chemical operations are performed 

 which no human skill can imitate nor art accomplish. Still 

 the pathways to these recesses are open to our search ; still 

 may we trace the blood thither : in other words, its vessels are 

 continued thither. And though we do not possess the means to 

 accomplish, nor enjoy the skill to imitate, the various and 

 wonderful works therein proceeding every the smallest mo- 

 ment, and though we may fall very short of ever arriving at the 

 modes of operation therein resorted to; — yet it is all open to 

 investigation ; all prepared to stand the scrutinizing ingenuity 

 and research of man ; all is calculated to augment the store of 

 his knowledge, to perfect him in reason, and to advance him 

 in intelligence and wisdom. 



It will be to our purpose if we avail ourselves of the testi- 

 mony of one or more of the skilful and patient microscopic 

 observers of the blood's circulation; for although they were 

 constrained to visit the reptile race of the animal kingdom, as 

 frogs and the like, — nay, a lower race still, as worms ; yet from 

 this quarter even have they raised up rich treasures of know- 

 ledge for our use and benefit. The celebrated Leeuwenhoeck 

 was among the first to employ that potent instrument the mi- 

 croscope in facilitating our descent, or rather our ascent, into 

 Nature's secrets; and his details of the wonders of the minute 

 creation are interesting in the highest degree. But as we may 

 have occasion to advert to this celebrated authority occasion- 

 ally in our way ; and as we are desirous of giving famihar il- 

 lustrations as we proceed, we will now adduce some interest- 

 ing testimony from the observations of Mi". Baker, who was 

 a Fellow of the Royal Society of London, and who devoted 

 much of his time to this kind of research. 



On the subject of the current and circulation of the blood, 

 he says, " The tail of a newt or water-lizard applied in a glass 

 tube in the manner directed for the eel, affords an entertaining 



prospect 



