The application of scientific method necessarily varies, therefore, according to the subject under investigation. Thus, the construction of a bridge and the calculation of an eclipse equally involve the bases of scientific method--viz., observation, deduction, and experiment; but each subject requires a special application of scientific method, suited to the varying nature of the subject of study. Consequently, biological research, in order to be scientific, requires a special modification of method, because the new factors of sensation and consciousness come into play in biology--factors which do not exist in astronomy, or geology, in mechanics, physics, or chemistry. In order to attain truth respecting biology, therefore, the facts concerning sensation and consciousness and their relation with, or the way in which these new factors modify the facts of, physics and chemistry must be carefully considered in this higher state which we call life, or the investigation is not scientific, no matter how interesting as an intellectual exercise. When first endeavouring to find a recognised definition of the term ‘science,’ I consulted the latest _Encyclopædia Britannica_ of our public library, thinking that from such an acknowledged authority a correct statement could there be obtained. To my surprise, I found that the word ‘science’ was not included in the list of subjects. Searching further in this record of nineteenth-century thought, under the head of ‘Biology’--that department which is ordinarily supposed to be the science of life as distinguished from the consideration of non-living things--the following principle was found to be laid down--viz., that there was no essential difference between organized and unorganized Nature, for life was simply a property of matter. It is well to weigh the argument for this doctrine, which necessarily destroys the essential idea of right and wrong, and removes the foundation of good and evil. It is set forth in the following manner: ‘The abstract-concrete sciences are mechanics, physics, chemistry.... Whilst their subject-matter is found in a consideration of varied concrete phenomena, they do not aim at a determination of certain “abstract” quantitative relations and sequences known as “laws,” which never are manifested in a pure form, but always are inferred by observation and experiment upon complex phenomena, in which the abstract laws are disguised by their simultaneous interaction.... These sciences of mechanics, physics, and chemistry have for their object to explain concrete phenomena by reference to the properties of matter set forth in their generalizations.’ The following important dictum in regard to biology is thus laid down: