38 



INSECTICIDES AND FUNGICIDES. 



A glance at the moisture figures in Table V shows that the variation 

 in the 9 samples is not very great, with a minimum of 6.23 per cent 

 and a maximum of 8.87 per cent. 



As to the percentage of ash, it must be remembered that these prepa- 

 rations are the powdered root of a plant. We would therefore expect 

 to find a rather high ash content, which would be much increased if 

 the roots had not been properly cleansed. The figures show that there 

 is at any rate no reason that the ash content should be above 15 per 

 cent, and evidently, with proper handling, this can be very much 

 reduced. Adopting, then, 15 per cent as the maximum amount allowa- 

 ble, it will be seen that samples 19836 and 19837 are very much above 

 this limit, and 19558 slightly above. 



Since the alkaloidal principles in the above 9 samples, on being 

 treated with concentrated sulphuric acid, act exactly similar to the 

 alkaloidal principles of 2 samples known to be pure, and also follow 

 fairly closely the color changes as indicated for the alkaloids of the 

 hellebores in chemical literature, these samples appear to belong to the 

 class of hellebores. The color changes seem to follow most closely 

 those indicated for cevadine, which might be expected if the above 

 samples are roots of Veratrwn viride, since this alkaloid appears in 

 quantities greater than the sum of all the other alkaloids. 



PYRETHRTTMS. 



The next group of substances to be taken up are the pyre thrums, 

 which include Pyrethrum roscum, or Persian Insect Powder, and 

 Pyrethrum eineraridefoliwn, or Dalmatian Insect Powder, and Buhach. 



The ground flower heads of these plants are used to kill insects. 

 Such preparations contain as their active principle a volatile oil, which 

 quickly oxidizes on exposure to the air to an inactive resin. a This oil 

 may be determined by extracting with ether and drying at a low heat. 

 Four samples examined by Hilgard gave the following results: 



Such powders sometimes contain either lead chromate, barium chro- 

 mate, or tumeric, to give them a bright yellow color or to palm off 

 some entirely different powder as one of the pyrethrums. 



METHODS OF ANALYSIS AND DISCUSSION. 



In making an analysis of these products the following determina- 

 tions were made: Moisture, ash (a large amount of which indicates the 



Hilgard. Report of the College of Agri. Univ. of California, 1879, p. 68. 



