32 THE CAUSES WHICH PllOPAGATE 



nothing dreadful, however, in the tunnel, save the ordinary risk 

 incurred on the rail ; and having^ settled on this route as the 

 most direct and economical, Macon and Paris formed but 

 pleasant breaks on the road. 



The object, then, of the present Avork, the faithful companion 

 and solace of my j^^reg-rination, is not to teach science dog- 

 matically after the fashion of a complete text-book, but rather 

 to stimulate a taste for individual research by indicating the 

 drift of modern investigation. Indeed, it seems to the author 

 not a little surprising that so much should be known regarding 

 the physiology of the marine Mollusca, and that Ave should 

 still possess so little certain acquaintance with the corresponding 

 life-history and structure of Insects ; and this must be the 

 more especially felt now that geology is taking rank as a 

 comj)rehensive pursuit, the contested theorems of which can 

 never be permanently established until specialists are found who 

 will devote their attentions to these much-neglected practical 

 subjects. 



Inconceivable aid to a fuller knowledge of the biology and 

 rank of species would be afforded by experts and insect fanciers 

 if, when out in the fields capturing their specimens, previous to 

 rendering them mere bits of innate form and formate colour by 

 the traditional pinch, acid, prick, or immersion in spirits, they 

 Avould first note down the date and locality of capture, and 

 placing them successively to the nose and ear, test their capa- 

 bilities for music and odours. The results, if any, should be 

 recorded on a label attached to the pin, or, if travelling, on the 

 dogs'-ears and envelope corners to which butterflies and the more 

 delicate booty are usually consigned. A few hurried cyphers 

 made at the time speak volumes — '' Vv/^^j New Forest — 

 Stridulates, Ion mesothorax ; ^^ or, "^ Odour, musk." And after- 

 wards a tally with fuller particulars and studies of habits, made 

 either on the spot, or in gauze-covered or glass-topped boxes, such 

 as are sold for geological specimens, or in an aquarium or 

 vivarium, together with such information as can be gained from 

 the lens, microscope, or other philosophical instrument, may be 

 inserted at leisure in a pocket-book or journal. From this data 

 a series of interesting cabinet labels may be easily constructed, 

 showing the stains of the secretions if not their analysis, or the 



