PUBLICATIONS. 9$ 



subject in the * Descent of Man,' but as soon as I 

 began to put my notes together, I saw that it would 

 require a separate treatise. 



My first child was bonbon December 27th, 1839, and 

 I at once commenced to make notes on the first dawn 

 of the various expressions which he exhibited, for I 

 felt convinced, even at this early period, that the most 

 complex and fine shades of expression must all have 

 had a gradual and natural origin. During the summer 

 of the following year, 1840, I read Sir C. Bell's admi- 

 rable work on expression, and this greatly increased 

 the interest which I felt in the subject, though I could 

 not at all agree with his belief that various muscles 

 had been specially created for the sake of expression. 

 From this time forward I occasionally attended to the 

 subject, both with respect to man and our domesticated 

 animals. My book sold largely; 5267 copies having 

 been disposed of on the day of publication. 



In the summer of 1860 I was idling and resting 

 near Hartfield, where two species of Drosera abound ; 

 and I noticed that numerous insects had been en- 

 trapped by the leaves. I carried home some plants, 

 and on giving them insects saw the movements of the 

 tentacles, and this made me think it probable that the 

 insects were caught for some special purpose. Fortu- 

 nately a crucial test occurred to me, that of placing a 

 large number of leaves in various nitrogenous and 

 non-nitrogenous fluids of equal density ; and as soon 

 as I found that the former alone excited energetic 

 movements, it was obvious that here was a fine new 

 field for investigation. 



