Robiqnet on A roma . Ill 



the developement of gases in space, is still that of the present 

 chemists. It has always, however, been easy to adduce some 

 facts which agree but awkwardly with this theory. There are 

 some bodies, such as musk, for example, which are not sensi- 

 bly volatile, and which yet spread a very strong odour. There 

 are also essential oils, the solutions of which in water are not 

 at all like the aroma of the part of the vegetable which has 

 yielded them. The odour of the essence of orange flowers 

 has not any analogy with the odour of the water distilled 

 from the same flower, and many others are in the same cir- 

 cumstances. There exists a considerable number of very 

 odorous flowers, such as those of the jasmine, the heliotrope, 

 and the tuberose, which are entirely destitute of essential 

 oil, or from which at least none can be obtained. It is, 

 therefore, to be supposed, that the real cause of odour in a 

 certain number of substances has not yet been ascertained. 

 I have had occasion to make some observations which support 

 this statement. 



Whilst making researches on the presence of prussic acid in 

 some vegetable substances, and particularly in the kernels of 

 stone fruits, I have arrived at some results which appear to me 

 sufficiently interesting to be published. 



There exists, as is well known, a strong analogy between 

 the odour of prussic acid, and of some vegetable products ; 

 and, indeed, according to the experiments of many chemists, 

 it is generally believed that it is to this acid that bitter 

 almonds, plum kernels, peach-flowers, the leaves of the laurel, 

 ^c, owe their odour and deleterious effects. M. Vauque- 

 lin and M. Schrader have discovered it in many vegetables. 

 It appears to me, however, difficult to admit that a product so 

 ephemeral and fugacious should be capable of remaining in 

 these substances for an indefinite time. How is it to be con- 

 ceived that the residue of bitter almonds, from which the fixed 

 oil has been separated by pressure, should remain impregnated 

 for an unlimited time, with this prussic odour. M. Martre of 

 Montauban and M. Vogel of Munich, though they admit the pre- 

 sence of prussic acid in bitter almonds have nevertheless 



