I860.] to the Science and Practice of Medicine, 261 



he who is engaged in extending medical science by publication or teach- 

 ing, must be less easily satisfied. His hypotheses must not only be ex- 

 planatory, they must also be verifiable by induction. They have to serve 

 a purpose, not limited to a present case, but calculated to exercise an 

 influence over future years and generations, as involving a principle. 



These doctrines the speaker could not illustrate before his audience 

 by taking them to the bedside of the patient, in reference to the im- 

 mediate practical hypothesis. But he brought forward one instance of 

 the uses of hypothesis in research. It related to the disorder called 

 senile apoplexy, the apoplexy of the aged. That the usual antecedents 

 of apoplexy, a congestive state of the circulation, should occur in an 

 aged brain might appear improbable ; and the more so, when it is con- 

 sidered that in age the brain undergoes a process of atrophy. Mean- 

 while, this improbability disappears under an hypothesis derived by 

 Dr. Rokitansky from this very assumption of an atrophic state of brain 

 in old age. Atrophy of a part implies diminution of size in that part ; 

 and this in the brain would imply a shrinking away of the substance 

 of the brain from the inner surface of the skull ; a fact often observed 

 after death of the aged. Now the space thus produced between the 

 brain and the skull, being impervious to air, is so far a vacuum ; so 

 that, atmospheric pressure continuing to exist on the rest of the body, 

 and being removed from the surface of the brain, it must, however 

 extenuated the subject, be replete with blood. It is needless to say 

 that this theory of the cause of cerebral congestion in the aged is 

 highly suggestive of a practical conclusion. The physician, being 

 enabled to explain the state of congestion induced in the brain into 

 conditions immediately resulting from a state of feebleness, is justi- 

 fied in declining depletory measures. 



Having thus discussed the value of a verified hypothesis, or in 

 technical language a theory, the speaker considered the less complete 

 forms of hypothetical reasoning. It happens in medical research, as 

 well as in practice, that an hypothesis, at present unverified by induc- 

 tion, but which would explain the case under consideration, derives 

 from this latter circumstance certain, though limited, amount of 

 weight. As, for instance, the occurrence of such symptoms as would 

 be present if a poison had been given, affords a presumption that a 

 poison has been given ; though while the poison is undetected, it 

 remains unverified. The hypothesis of temperaments again, though 

 unverified, is luciferous ; it may eventually obtain inductive proof, and 

 be fitted to take its place in the history of our science. 



But an hypothesis, whether for immediate practice or for purposes 

 of research, may not only be unverified ; it may also be unexplana- 

 tory. This latter defect, occasional among medical writers, and 

 frequent in the practice of those by whom the force of words is not 

 justly estimated, the speaker illustrated from the work of Mr. Charles 

 Darwin. He presumes the terms " natural selection " to constitute an 

 instance of it ; as seeming only to explain his process of transmutation 

 of animals. 



Vol. III. (No. 32.) t 



