46 Gmrvpositae, Ericaceae [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 efEect." 



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 Lactucariwm, includes Lactucone, Lactucm, 

 and Lactucic Add, 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 (C14H22O), and the 

 bitter taste is due to Lactupicrine, Lactucin and Lactucic Acid. In 

 the leaves of L. mrosa, Dymond found traces of Hyoscyamine or 

 a similar substance (Jour. Chem. Sac, 1892, Vol. 61, p. 90). 



Symptoms. Intoxication is produced similar to that caused by 

 poppy heads ; the narcotic effects are dominant (Comevin). 



REFERENCaSS. 

 11, 73, 81, 130, 213, 240. 



Bhododendion {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 Veterima/ry Journal (1906), and two in the Vele/rirmrian (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 eaiten after a heavy faU of snow. Chesnut includes R. maxi- 

 mum as one of the thirty most poisonous plants of the United States. 

 According to Comevin, R. ferrugirmim 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 willuigly 

 browse the young shoots and leaves. R. caUfornicum is said to be 

 poisonous to sheep in Oregon. R. Chrysanthum, the leaves of which 



