PRUSSIC ACID IN WILD CHERRY LEAVES I 23 



from paralysis of the lungs. In some cases there is consider- 

 able frothing at the mouth ; in all there is a very perceptible 

 odor of prussic acid in the breath." 



According to Blythe, the fatal dose of the anhydrous acid, 

 for an adult person, is about one grain, or 65 milligrams. At 

 this rate, about one half pound of the black cherry leaves mav 

 be considered as a fatal quantity for a cow to eat. 



During the work this summer several samples each of culti- 

 vated plum {Pruiius dornesticana)^ peach (yPrunus persica) ^ 

 apple {Pyrus malus)^ and cultivated cherry leaves (^Prunus 

 cerasus) were analyzed. Those of the plum, apple, and, 

 rather singularly, cultivated cherry yielded no acid whatever. 

 Peach leaves showed from 77 to 100 milligrams per 100 grms. 

 leaves; so that, in this connection, they might be classed with 

 the leaves of the wild red cherrv. 



To these data may be added a few figures recorded by Blythe 

 in his work upon poisons: One hundred grams of bitter al- 

 monds {Affiyg'dahts communis^ ^ in the form of pulp, yield 250 

 milligrams prussic acid ; the same amount of kernels from 

 cherry stones yields 170 mgs. ; leaves of the cherry laurel (^Pru- 

 72US lauro cerasus)^ occurring in Europe and in Mexico, 39 

 mgs. ; kernels of peach, 164 mgs. ; plum, 56 mgs. ; apple seeds, 

 35 mgs. The stones of all these species must therefore be re- 

 garded as dangerous ; the fruit, in every case, so far as can be 

 ascertained, is harmless. 



CONCLUSIONS 



The leaves of the wild black cherry are the most poisonous 

 of the three species investigated, though all are dangerous. 



Both the wilted and fresh leaves are poisonous, while the 

 dried are to be regarded with suspicion. 



Vigorous, succulent leaves from young shoots, which are the 

 ones most liable to be eaten by cattle, are far more poisonous 

 than the leaves from a mature tree or stunted shrub. 



Leaves wilted in bright sunlight to about 75 per cent, origi- 

 nal weight, or until they begin to appear slightly limp and to 

 lose their gloss, yield the maximum amount of prussic acid. 



