260 DR ANDERSON ON THE DISTILLATION OF ANIMAL SUBSTANCES. 
series. These pyrrol bases I conceive, therefore, to be substances formed by the 
coupling of the picoline series with some substance which yields the red matter 
to which I have alluded. I have not as yet, however, pursued the investigation 
of these bases, but shall communicate the result of their examination in a future 
paper. 
The Non-basic Constituents of Bone Oil. 
I have as yet directed very little attention to this branch of the subject. I 
have found, however, that when the most volatile part of the oil, after sepa- 
ration of the bases, is repeatedly rectified, it improves in odour, and at length 
there is obtained a substance which, when acted upon by nitric acid, and then by 
sulphide of ammonium, gives the reaction of aniline,—indicative of the presence of 
benzine in the oil. It is probable, therefore, that this series of homologous carbo- 
hydrogens forms a part of the oil, but not the whole of it, for I have found that 
when the oil is boiled for some time with potass, ammonia is evolved, and on 
supersaturating the potash solution with sulphuric acid, the odour of butyric acid, 
or at all events of one of the fatty acids, becomes apparent; from which phenomena 
I draw the conclusion that it also contains the nitriles of these acids. 

