THE HAMILTON ASSOCIATION. 65 



in 1874 have been experimented upon in various ways, and the 

 result shows that they absorb through the tissue of the leaf by 

 special organs the material required for their food, and the actual 

 agent in the digestion of insects is a ferment of nature similar to 

 pepsin, which is secreted only during the absorption of some 

 digestible substance. Insects steeped in lithium have been placed 

 on these carnivorous plants, and the roots, when boiled some 30 

 hours afterwards, afford the colouring matter of the lithium, showing 

 that it has been absorbed and distributed throughout the whole 

 plant tissue. 



Up to the year 1837, the efforts of naturalists were chiefly 

 directed towards the perception of differences and the creation of 

 species. But in that year Schleiden told the world, after long 

 research, that as the lowliest members of the vegetable kingdom are 

 each in themselves an individual cell having life and activity, so the 

 highest orders of plants were only congeries of such individuals 

 moulded into a thousand shapes and adapted to different purposes. 

 He enunciated the principle that the story of a plant is to be studied 

 through the vital history of its composing cell elements, and pro- 

 claiming the microscopic vegetable cell as the unit of vegetable 

 creation, he exalted it to a place of honor — the key to the cabinet 

 of Vegetable Physiology. 



His researches induced Schwann to apply to the animal world, 

 the same method of enquiry whieh Schleiden had inaugurated 

 among plants, and he in his turn made known the sublime truth 

 that the law of formation and reproduction which prevails in the 

 vegetable, rules also over the animal creation — the scheme is the 

 same, the cell the element of being. Bones, cartilages, muscles, 

 nerves and every tissue were traced to their origin in cell growth, 

 the universality of which binds all created beings in one sublime 

 connection and proclaims a common law of growtn. The vital pro- 

 cesses of the body are carried on by cell action; secretion, absorption, 

 exhalation, nutrition, chemical change and vital change, all indicate 

 only phases in the history of cell life — that epitome of all organic 

 life. But while Schleiden and Schwaun were working amidst the 

 mysteries of structure, Professor Owen took up the question, and 

 what the former had done for structural anatomy, Owen did for the 

 anatomy of form. The man, the bird, the reptile, the fish, the 

 saurian and the monsters of pre-adamite earth seemed to be sepa- 



