Aphysician, for example, is called by apatient. His orig- inal material of experience is thereby provided} it requires a stretch of useless imagination to fancy that the ill man is a mass of sense data organized by categories. This experienced object sets the problem of inquiry. Certain clinical operations are performed, sounding, tapping, getting registrations o pulse, temperature, respiration, etc. These constitute the symp- toms} they supply the evidence to be interpreted. The philoso- pher or logician, looking on, sees they are that part of the original object which is capable of being presented in observa- tion as that is sensibly present. The results are not all that is or can be observed, but are those phases and portions of the experienced whole that are judged to be relevant to making an inference as to the nature of the ailment. The observations mean something not in and of themselves, but are given meaning in the light of the systematized knowledge of medi- cine as far as that is at the command of the practitioner. He calls upon his store of knowledge to suggest ideas that may aid him in reaching ajudgment as to the nature of the trouble and its proper treatment.