INTRODUCTION. xxi 



studies, but he addressed some of his best letters on philoso- 

 phical subjects to her. After she had lost her mother, in 1783, 

 he frequently expressed a wish that she would become his neigh- 

 bour in America. Accordingly, in 1786, she went with her 

 children to Philadelphia, where she lived until 1792, and then 

 removed to Bristol, in Pennsylvania, where her eldest son, 

 William, had established himself, and where she closed a well- 

 spent life on the 14th of October, 1795. Her second son, 

 Thomas Tickell Hewson, who was an eminent physician, and 

 her daughter, Mrs. Caldwell, were both living at Philadelphia 

 in 1837. Her son William died at Vera Cruz in 1802. 1 



In the hope that some further information might be obtained 

 from America concerning Mr. Hewson or his descendants, the 

 printing of this sheet has been long delayed ; but my inquiries 

 have only elicited that his son, Dr. Hewson, is at present the 

 respected President of the College of Physicians at Philadelphia. 



We are now to consider Mr. Hewson's writings. In 1767 

 his paper on the Operation of perforating the Pleura in cases of 

 Air in that Sac, was communicated by Dr. Hunter and pub- 

 lished in the third volume of the ' Medical Observations and 

 Inquiries.' 



The second Dr. Monro had before, in his lectures, proposed 

 the same operation, of which, when Hewson was informed, he 

 made a suitable acknowledgment to Dr. Monro, and published 

 it in the Appendix to the first and second editions of the 

 ( Inquiry into the Properties of the Blood/ 



Hewson's three papers on the Lymphatic System in Birds, 

 Amphibia, and Fishes, appeared in the 'Philosophical Trans- 

 actions' for 1768 and 1769, and form the substance of the fourth, 

 fifth, and sixth chapters of the Second Part of his 'Experimental 

 Inquiries/ published but a short time before his death in 1774, 

 and dedicated to Dr. Franklin, who had shown Hewson great 

 regard since his marriage to Miss Stevenson. The first paper 

 was read before the Royal Society on the 8th of December, 1768; 

 and the discovery of the vessels which correspond in the lower 

 vertebrate animals to the lacteals of mammalia was claimed by 



1 Franklin's Letters and Miscellaneous Papers, with Notes, by Jared Sparks, 12mo, 

 London, 1833 ; and the Works of Benjamin Franklin, with Notes and Life of the 

 Author, by Jared Sparks, 10 vols. 8vo, Boston, 1840. 



