248 VETEEINAEY TOXICOLOGY 



nervous centres; flesh pale, capillaries empty, the great 

 vessels and right heart filled with black blood. 



Chemical Diagnosis. — Nicotine, being volatile, is 

 separated by distillation in a current of steam from the 

 organic material made alkaline by caustic alkali. The 

 distillate then contains the oily, pungent, and characteristic 

 nicotine. In the absence of definite chemical reactions 

 physiological tests should be made. 



When the material is in sufficient quantity, it is very 

 desirable to perform comparative tests to decide between 

 nicotine and conine. An ether solution of nicotine, mixed 

 with an ether solution of iodine, gives a precipitate, or, if 

 there is but a trace of nicotine, a turbidity, and gradually 

 long red crystals form, which reflect blue (Eoussin's test). 

 Conine does not give this reaction. Another distinction 

 depends on the fact that a cold saturated (1 to 90 of water) 

 solution of nicotine remains clear on warming, whereas a 

 similar solution of conine becomes turbid, since conine is 

 less soluble in warm than in cold water. Nicotine hydro- 

 chloride first separates as a resin, slowly becoming 

 crystalliae, whilst conine gives at once a crystalline 

 hydrochloride. 



SCROPHULARINE^. 



This family contains many poisonous genera, of which 

 those found in Britain and on the Continent are Digitalis, 

 Scrophularia, Pedicularis, Rhinanthus, Melampyrum, Ver- 

 bascum, and Linaria, whilst Gratiola is native to South- 

 Eastern Europe. Those members which have been defin- 

 itely studied have been found to contain glucosides of 

 the digitalis and saponin classes. 



Dig-italis. 



Botanical ChaFaeters. — TheDigitalis purpurea (Pig. 36), 

 common foxglove, finger flower, or dead men's bells, is a 

 very common weed, often cultivated as a garden plant. It 

 frequents dry, hilly wastes, roadsides, and banks. Being 



