4 PR. BRACKENRIDGE CLEMENS LETTERS. 



en passant, I have just been informed by that house the 

 Weekly Intelligencer for 1856 is out of print. Can you obtain 

 a copy and have it charged to me at their house, 219, Regent 

 Street, London? 



Should I not, even at the risk of being egotistical, give 

 you some introduction to myself? I am yet young, as you 

 have perhaps conjectured, a physician by education and pro- 

 fession, and a graduate of the University of Pennsylvania ; 

 but here, I fear, my scientific qualifications to your regard 

 must find an end. I stand merely on the shores of Science, 

 gazing on the immensity before me. And as I follow with 

 my eyes the full-freighted Intellects, which, fanned by the 

 wings of Fame, sail over its placid waters in search of un- 

 known Truths, I am filled with doubts and the feelings of 

 despair, which arise from a consciousness of my own imper- 

 fections. 



I shall, I fear, prove an unprofitable correspondent. I have 

 never published a single sentence in relation to my studies, 

 although I have, of course, kept a note-book, in which such 

 observations as I deemed worthy of record have been noted. 

 I have proposed to myself several problems for solution, if 

 possible, during this season ; some in relation to the physio- 

 logical uses of various organs, in order to understand their 

 value and significance in classification ; the determination of 

 the forces by the action of which wing-dilatation in Lcpi- 

 doptera is produced ; and I am now especially endeavouring 

 to comprehend the signification of the neuration of their 

 wings. I worked at this subject for some time before knowing 

 it had been introduced into modern classification, endeavour- 

 ing to ascertain whether it could not be used as a dominator 

 character in the formation of families and genera. I have 

 thus far failed to satisfy my own mind in regard to its real 

 value, chiefly in consequence of being unable to recognize a 

 sufficient number of the genera of each family. Nevertheless, 

 in the absence of other means of classification, as, for instance, 

 the capture of a new imago, or the examination of mutilated 

 specimens, I have relied on it exclusively for the determina- 



