396 GROWTH OF THE 'ORIGIN.' [1846. 



think myself ill-used, for I remember your saying you would 

 make some remarks on the weather and barometer, as a guide 

 for the ignorant in prediction. I had also hoped to have 

 perhaps met with some remarks on the amount of variation in 

 our common species. Andrew Smith once declared he would 

 get some hundreds of specimens of larks and sparrows from 

 all parts of Great Britain, and see whether, with finest meas- 

 urements, he could detect any proportional variations in beaks 

 or limbs, &c. This point interests me from having lately 

 been skimming over the absurdly opposite conclusions of 

 Gloger and Brehm ; the one making half-a-dozen species out 

 of every common bird, and the other turning so many re- 

 puted species into one. Have you ever done anything of this 

 kind, or have you ever studied Gloger's or Brehm's works ? 

 I was interested in your account of the martins, for I had just 

 before been utterly perplexed by noticing just such a pro- 

 ceeding as you describe : I counted seven, one day lately, 

 visiting a single nest and sticking dirt on the adjoining wall. 

 I may mention that I once saw some squirrels eagerly splitting 

 those little semi-transparent spherical galls on the back of oak- 

 leaves for the maggot within ; so that they are insectivorous. 

 A Cychrus rostratus once squirted into my eyes and gave me 

 extreme pain ; and I must tell you what happened to me on 

 the banks of the Cam, in my early entomological days : under 

 a piece of bark I found two Carabi (I forget which), and 

 caught one in each hand, when lo and behold I saw a sacred 

 Panagaus crux major ! I could not bear to give up either of 

 my Carabi, and to lose Fanagceus was out of the question ; so 

 that in despair I gently seized one of the Carabi between my 

 teeth, when to my unspeakable disgust and pain the little in- 

 considerate beast squirted his acid down my throat, and I lost 

 both Carabi and Panag&usl I was quite astonished to hear 

 of a terrestrial Planaria ; for about a year or two ago I de- 

 scribed in the * Annals of Natural History ' several beautifully 

 coloured terrestrial species of the Southern Hemisphere, and 

 thought it quite a new fact. By the way, you speak of a 

 sheep with a broken leg not having flukes : I have heard my 



