720 
Proceedings of the Eoyal Society 
51. “ Hydrastin,” a resinous matter, prepared from tlie root of 
the Hydrastis canadensis , is a hepatic stimulant of considerable 
power. It also slightly stimulates the intestinal glands. 
52. “ Juglandin,” a resinous matter, prepared from the root of 
the Juglans cinerea , is a hepatic stimulant of considerable power. 
It also slightly stimulates the intestinal glands. 
Thus, by means of a new and precise experimental method, the 
physiological pharmacology of one of the most important organs of 
the body has been in this research worked out as far as at present it 
ajepears desirable to proceed, and knowledge that is definite and 
reliable, because obtained by a method of accurate measurement, 
after the elimination of disturbing factors, has by this research been 
substituted for the vague traditions of the past. 
The effects of fifty-two medicinal agents upon the liver have been 
investigated, and the vast majority of the conclusions are in complete 
harmony with the results of clinical observation. Very many new 
facts are, however, given to the physician, and even as regards well- 
known substances, our knowledge of their effects on the liver is 
now of a character very different from that which previously ob- 
tained. 
All the experiments relate to the bile-secreting and not to the bile- 
expelling mechanism. The authors do not intend to investigate the 
effects of medicinal agents on the latter, as this point appears to 
them one of very minor importance compared with the subject of 
the above research. 
The following remarks indicate the position in pharmacology of 
the above results. Of necessity, the influence of a drug upon a 
diseased state is the ultimatum of pharmacology, and every experiment 
upon a healthy bodily system, whether of man or animal, is merely 
ancillary to experiments with the drug in disease. Having discovered 
that this or that drug stimulates the healthy liver of a dog, we do 
not infer that it must also stimulate the human liver in health, and 
still less do we conclude that it must also have this action in disease. 
The experiments on the healthy liver of the dog, on the normal and 
on the abnormal human liver, are three sets of experiments closely 
related, but still distinct. The facts derived from any one of the 
three sets cannot be substituted for those of the other two. Each 
set of facts has its own proper place. The above research, therefore, 
