1016 Wisconsin Academy of Sciences, Arts, and Letters. 
cubic centimeter of the former. Filter and divide the filtrate into several parts. 
Prepare solutions of different dilution from these parts by adding a 
measured amount of water to each. Then immerse 5 earthworms in each 
of these solutions and note the maximum dilution in which all 5 are killed. 
For computing the relative value of the preparation compare these re¬ 
sults with those obtained when using a standard solution prepared by dis¬ 
solving a weighed amount of filix acid, filmaron or albaspidin in water in 
the same manner as described above for the oleoresin. In the case of these 
standard solutions the limit of toxicity is given as follows: filmaron, 3 
parts in 1,000,000; filix acid 4 parts in 1,000,000; albaspidin 1 part in 
100,000. 
Adulterations 
The efforts which have been made in recent year& to stand¬ 
ardize this preparation have resulted in the discovery that the 
commercial article is very frequently adulterated, the latter 
being accomplished in a variety of ways. 
The method usually resorted to by unscrupulous manufac¬ 
turers in order to increase their profits consists of diluting the 
finished product with some comparatively cheap material. 
Castor oil 1 has generally been used for this purpose. In some 
cases, the oleoresin is prepared from deteriorated brown rhi¬ 
zomes and made to assume the green color of the official pre¬ 
paration by the addition of chlorophyll or salts of copper. 2 
Adulteration, however, is not limited to the addition of for¬ 
eign materials to the finished product, but may take place in 
the drug from which the oleoresin is prepared. The forms in 
which the drug may be contaminated are conveniently classed 
under three heads, viz.: (a) the substitution of old deteriorated 
rhizomes for the fresh material, (b) the admixture of chaff 
and dead stipe bases with the rhizomes, and (c) the admixture 
of rhizomes of unofficial species of fern with those of the 
official species. For a discussion of these conditions, see under 
“Drug used, its collection, preservation, etc.” 
1 Parry (1911) ; Evans Sons, Lescher and Webb (1911) ; and others. 
2 Weppen and Lueders (1892); Beckurts and Peters (1893); Fendorff 
(1913) ; and others. 
A trace of copper is usually present in the commercial product as a result 
of the use of copper utensils in the manufacture of the preparation. (See 
under “Ash”). 
