16 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



some other convenient place. A considerable number of separate 

 deposits are made during the year. 



The slug3 and some species of snails were considered by the Romans 

 to possess medicinal properties, and this belief continued, among the 

 nations of Europe, through the Middle Ages down to comparatively 

 recent times. There is hardly a disease, internal or external, of man 

 or the domestic animals, in which, according to the statements of 

 authors, they have not proved beneficial ; and the relations concerning 

 them are numerous and truly marvellous. The testaceous rudiment 

 of the Limax acquired in this respect a pre-eminence above the animal 

 itself, and enjoyed a high rank among the numerous bezoars and amu- 

 lets which were supposed to protect the body from evil influences, and 

 to impart health and activity to its various functions. 1 The accounts 

 of their virtues, copied from one author to another, on the authority of 

 names, show how easily error is perpetuated, and how difficult it is to 

 eradicate from the public mind a false opinion which has once obtained 

 a footing. A full relation of all the absurdities which gained credence 

 would form a curious page in the history of credulity and superstition. 

 The more general diffusion of knowledge at the present day has dis- 

 pelled these ideas in a great degree ; but some relics of them still linger 

 among the rural population of many parts of Europe, In this country 

 no such belief has ever prevailed ; and so hidden and clandestine are 

 the habits of the animals, that but a small part of the population is 

 aware of their existence, and those who are familiar with them view 

 them with such feelings of disgust as would effectually prevent their 

 use either as medicine or as food. 2 They have also from very early 

 times been used in the preparation of cosmetics ; and the water pro- 

 cured from them by distillation, no longer than two or three centuries 

 ago, was much celebrated and used by ladies, to impart whiteness and 

 freshness to the complexion. 



Although the title of this work embraces only the terrestrial genera, I 

 have actually included all the Geophila, and thus have been forced to 

 treat Onchidella, whose habits are strictly marine. At the same time 

 I have omitted several strictly terrestrial genera which are not air- 

 breathing, but furnished with gills, such as Helicina. 



1 As late as the close of the sixteenth century Helling published a dissertation with 

 this title : " Ossiculorum limacum usus in febribus." During the year 1863 a syrup of 

 snails was prescribed to members of my family by two regular French physicians in Paris. 



3 They are, however, frequently imported as an article of food for foreign residents of 

 our cities. 



