Nor are the symptoms produced by the operation of narcotic poisons so distinct as to escape the possibility of being confounded with those of spontaneous disease. They may, for instance, simulate those of apoplexy, or epilepsy; but the history of the case, the odour of the breath, and the subsequent examination of the body after death, will generally clear up the difficulties which may at first present themselves. But we shall have occasion to consider this subject hereafter; the difficulties of the case are well illustrated by the evidence on the trial of _Donellan_, for the murder of _Sir Theodosius Boughton_, with laurel water, for which see _Appendix, p._ 243. Before we quit the subject which involves the consideration of our fluids degenerating, under particular circumstances, into poisons, we may just notice the opinion of some foreign chemists, that in certain diseases the _Prussic acid_[177] is generated in some of the fluids of the animal body. We are not inclined to accede to this proposition, because during life we do not think the chemical decompositions, known to be necessary for the production of this substance, can ever take place. At all events, it must be preceded by a state of the system which would necessarily prevent the chance of any medico-judicial fallacy. Q. II. _Whether organic lesions, similar to those produced by poisoning, may not occasionally result from natural causes?_ In entertaining this question, we are prepared to meet with numerous alleged difficulties; but as many of them appear to have arisen, rather from the ignorance or carelessness of the operator, than from the natural obscurity of the subject itself, we are inclined to hope that by getting rid of the former source of fallacy, we shall be enabled to examine with some satisfaction and advantage, those which, in a greater or less degree, will be liable to baffle the researches of the more experienced anatomist.