Dr. H. Johnson on the Diva-gence of Plants. 17 



on the moors they escape the enemy by wearing a close boot. 

 After walking some time upon gravel, far removed from any 

 plant whatever, the stocking will be found sprinkled with 

 them, when, running rapidly upwards, they ensconce them- 

 selves wherever the dress is most closely confined to the body. 

 Animals, particularly horses, suffer dreadfully from this cause, 

 the tender skin of the lips and nose being frequently covered 

 with nests of harvest-bugs, which have fixed there during 

 grazing, but which probably cannot bury themselves as in the 

 human being from the toughness of the skin. The cat's 

 whiskers have a scarlet spot at the insertion of each hair *, and 

 she bites her paws all day, yet does not relinquish her fa- 

 vourite bask on the warm gravel, which probably is the cause 

 of her annoyance, because the rabbits, shut up in a building, 

 though fed even on the freshest of kidney-bean plants, are 

 not aware that harvest-bugs exist. 



If it be asked where was the embryo harvest-bug,— where 

 was the insect whose life, beginning as it would seem with the 

 greatest heat of summer, ended with the first cold of autumn, — 

 during the intermediate nine months ? we may reply, Probably 

 buried in embryo in the soil. But research would afford no 

 information on this subject, from the minuteness of the insect. 



Rectory, Hayes, Kent, March 1836. A. M. H. 



V. On the Divergence of Plants^ and its Analogy to the Irri- 

 tability of Animals. By Henry Johnson, M.D. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



IN No. 33 1 of your valuable Journal you have done me 

 the favour to insert a short communication on the subject 

 of a newly discovered property in plants supposed to be ana- 

 logous to animal irritability, and which communication has 

 been honoured by the notice of two " friends, " whose in- 

 quiries and remarks are appended to my paper. 



I take great shame to myself for having allowed a whole 

 year to elapse without any attention having been paid, or at 

 least any answer returned, to these very valuable and obli- 

 ging notices, for which, whilst I apologise for my apparent 

 neglect of them, allow me to offer through you my best thanks 

 to your ingenious and able correspondents. 



* They probably do not breed in the animal skin any more than in that 

 of their su[)erior prey, because though visible in large groups, each indi- 

 vidual seems equally mature. 



t Lond. & Edinb. Fiiil. Mag., March 1835, vol. vi. p. 164. 

 Third Series. Vol.9. No. 51. ,7?//y 1836. D 



