46 Compositae, Ericacex [CH. 
and Gordon say that " we have been informed that this European plant 
now a national pest is sometimes eaten by cattle, on whom it has been 
observed to have had an injurious effect." 
Toxic Principle. Authorities differ as to the substances to which 
the toxic property, if any, is to be attributed. According to Ludwig 
the milky juice, known as Lactucarium, includes Lactucone, Lactucin, 
and Lactucic Acid, the second of these being the narcotic substance. 
Nearly half the weight of Lactucarium (a form of dried juice) consists 
of the tasteless inodorous Lactucone or Lactucerin (C 14 H 22 0), and the 
bitter taste is due to Lactupicrine, Lactucin and Lactucic Acid. In 
the leaves of L. virosa, Dymond found traces of Hyoscyamine or 
a similar substance (Jour. Chem. Soc., 1892, Vol. 61, p. 90). 
Symptoms. Intoxication is produced similar to that caused by 
poppy heads ; the narcotic effects are dominant (Cornevin). 
REFERENCES. 
11, 73, 81, 130, 213, 240. 
ERICACEAE. 
Rhododendron (Rhododendron sp.). The literature points to there 
being no doubt as to the poisonous character of a number of species 
of Rhododendron, and indeed most species are suspected. Animals do 
not appear to eat Rhododendrons very extensively, but both English 
and Belgian veterinary surgeons have published records of poisoning 
of sheep and goats by R. ponticum. Suspected cases were recorded in 
the Journal of the Board of Agriculture (1907 and 1914); three cases 
of cattle poisoning in the Veterinary Record (1900, 1906, and 1907); one 
of calves in the Veterinarian (1859); and three of sheep-poisoning one 
in the Veterinary Journal (1906), and two in the Veterinarian (1865) ; but 
these cases were not all fatal. The death of 19 out of 21 cross-bred 
Scotch lambs due to eating R. ponticum was reported by C. T. Baines 
in the Journal of the Land Agents Society (Aug. 1914, p. 373). The 
plant was eaten after a heavy fall of snow. Chesnut includes R. maxi- 
mum as one of the thirty most poisonous plants of the United States. 
According to Cornevin, R. ferrugineum causes frequent poisoning of 
animals which graze on the plateaux where it grows especially sheep 
and goats, the latter providing the most victims, as they willingly 
browse the young shoots and leaves. R. californicum is said to be 
poisonous to sheep in Oregon. R. Chrysanthum, the leaves of which 
