xlvi INTRODUCTION. 



described motions in the fibrils during the coagulation of fresh 

 blood. 



Magnus Falconar 1 published the third part of the Experi- 

 mental Inquiries in 1777. He has explained his share of the 

 work in the preface. He appears to have written the last 

 four chapters with great care and fidelity ; but it is probable 

 that Hewson would have altered some of the statements, had 

 he ever seen them. 



Hewson's observations are more exact and complete than 

 any that had before been made on the red corpuscles. He 

 finally exploded the error of Leeuwenhoek that those of the 

 mammalia are spherical, by proving their flat figure, and show- 

 ing that they may accordingly be seen laid one against another 

 like coins. He proved that water renders them spherical, that 

 their flat shape is preserved by the saline matter of the serum, 

 or by a weak solution of a neutral salt, and that they are con- 

 tracted or shrivelled by a strong solution. His demonstration 

 of the nucleus and vesicle in the corpuscle of lower vertebrate 

 animals is excellent. He observed the important facts, now 

 generally admitted, that there is a difference of character 

 among the corpuscles of the same blood; that they are larger 

 in the embryo than in the adult; and that they split into 

 an irregular number of pieces, under certain circumstances, 

 from the circumference to the very centre, while each of these 

 portions retains its red colour, contrary to a leading tenet of 

 Leeuwenhoek's hypothesis. 



He was the first to examine accurately the fluid of the 

 lymphatic system, of the thymus and of the vessels which 

 run from it into the veins at the lower part of the neck. He 

 described the corpuscles common to all these fluids, and saw 

 the pale globules in the blood. The lymphatic vessels just 

 mentioned of the thymus, he concluded, like Sir Astley Cooper 



1 Mr. Falconar was born at Cheltenham, in Gloucestershire, in November, 1754. 

 He married Hewson's sister, and died of pulmonary consumption at Bristol, March 

 24, 1778, at the age of 24. He was a man of great application and dexterity, and a 

 good speaker. The sale of his collection of anatomical preparations, which included 

 those made by Hewson, produced upwards of 900. (Dr. Simmons's Life of Dr. 

 Hunter, p. 58.) Mrs. Hewson (Mr. Pettigrew's Life of Dr. Lettsom, vol. i, p. 146, 

 of the Correspondence) says that her husband desired on his death-bed that he should 

 be succeeded in the Anatomical School by Mr. Falconar. 



