294 EMPLOYMENT OF COLLODION. 



be observed that the dense texture of the wood prevents the 

 introduction of much water at a time, that the cuttings are very- 

 slender, and the leaves very large. Plants that are differently 

 constituted can bear no such treatment. Let it be tried with a 

 succulent plant, and the cutting would be rotten in a week. 

 Succulent plants, indeed, will generally do best where there is 

 no more moisture in contact with them than what the air holds , 

 suspended. When they are gummy, or milky, or resiuous, it 

 is necessary to let the end which is to be plunged in the ground 

 become dry, so that the mouths of the veins may contract, and , 

 thus hinder the too rapid introduction of water. Mr. Neumann's 

 mode of doing this is ingenious. When he takes off cuttings of 

 Araucarias, Euphorbias, Vahea gummifera, and such plants, he 

 plunges them in a pot, in damp earth, not pressed down, with 

 their lower end upwards, so that the latter only is exposed to 

 the air, the whole head being buried. By this means he dries 

 the wound, without allowing any of the water of such cuttings 

 to escape. After leaving them for 34 or 86 hours, or even 

 more, he wipes the end, so as to remove the gummy matter that 

 has exuded, and then puts them in again in the usual way, 

 when they take, and the more freely according as the wound is 

 neatly made. 



In order to meet the difficulty of maintaining quttings in an 

 equable state with respect to both external and internal mois- 

 ture, Mr. Lowe has proposed to dip their ends in collodion, 

 a substance possessing great adhesive power, impenetrable by 

 water, and impervious to air. Believing that the great difficulty 

 attendant upon the multiplication of plants by cuttings arises 

 from the tissues rotting by the excessive introduction of water, 

 which the cuttings cannot decompose, or throw off as vapour, it 

 occurred to him that if the fresh end of a cutting were smeared 

 with collodion the injurious access of water would be cut off, and 

 the risk much diminished. The result of his experiments con- 

 firmed his anticipations. Out of 26 coUodionised cuttings of 

 stove plants 23 grew, while only 12 out of 26 grew when the 

 collodion was omitted. In like manner, of 33 coUodionised 

 cuttings of greenhouse plants 28 grew, but only 11 out of the 

 same number took in the absence of the collodion. Similar 



