198 



moving It the process of secretion was found to be kept up for 

 several weeks. He proved also that the honey was a product 

 of the single leaf to which the gland belonged. By darkening the 

 leaf no honey was secreted. It is also said that these organs are 

 much more common among the tropical plants than among those 

 in the temperate zones, all of which facts go to make probable the 

 theory of plant adaptation to its surroundings. E. L. G. 



Peculiar Properties of AdJiatoda vasica, Nees, — One of the 

 most interesting, and, as it may also prove, important of recent 

 investigations of plant properties is described by Mr. David 

 Hooper, Government Quinologist in India, in the Pharmaceu- 

 tical Journal and Transactions of April 7, and is in relation to 

 the Acanthaccous shrub Adhatoda vasica, Nees. The leaves, 

 which are variously used as a domestic drug and dye, are chiefly 

 interesting on account of their use in agriculture. Great injury 

 is inflicted on the rice crop of India by the masses of Algai and 

 other aquatics which infest the partially submerged grounds. It 

 was noticed by Dr. G. Watt that the natives protected them- 

 selves against these enemies by casting into the water large 

 quantities of the Adhatoda l^^ve^. This observation led Mr. 

 Hooper to undertake the examination of the plant. He suc- 

 ceeded in isolating a peculiar acid w^hich he called adhatodic 

 acid, and an alkaloid which he called vasicine, the adhatodate of 

 vasicine being regarded as the active principle of the leaves. 



*' A sample of pond-water containing Spirogyra and numer- 

 ous animalcules was mixed with a strong infusion of Adhatoda 

 leaves. The chlorophyll gradually disappeared from the weeds, 

 and the cells became broken up. The oxygen was given on 

 with less frequency, and at length ceased. Some insect pupae 

 rose to the surface of the water and there died. Numerous 

 Paramecia remained active for some time, but eventually suc- 

 cumbed to the action of the poison. In twenty-four hours the 

 beaker containing the water showed only a brown mass lying at 

 the bottom, while some water in a beaker at the side, without 

 this treatment, contained the green aquatic weeds evolving oxy- 

 gen, and the animalcules alive." 



Farther experiments upon insect vermin, and upon frogs, 



