Page:Popular Science Monthly Volume 84.djvu/428

424 to flow from the host to the tissues of the parasite carrying substances in solution. The experimentation in this subject consisted, first of all, in forming artificial parasitical relations between plants in order to obtain

 The lower line shows the weight decreasing from 38 kg. to 28.8 kg. in five years. The upper line shows the rate of daily loss which fell from 10.6 g. to 3.5 g. during this time. The rate of loss is not directly proportional to the succulence or amount of water present.

a number of couples which might be joined as host and dependent, and also equally important to find others which might not enter into this relation.

The succulents with their accumulations of water offered suitable material and, using these as artificial hosts a number of species were caused to live on them parasitically for months or even years. Having this material, analyses of the sap or watery solutions of the two plants