Half Hours with Modern Scientists

action actual energy ammonia analogy animal appear atoms beam blue body brain called carbonic acid cell cerebellum cerebral hemispheres characters chemical chemistry circulatory system condition constituents contractility converted correlation Darwin David Hume difference dust earth electricity ether waves evidence exhibited existence fact genera genus geologic geological periods germ heat higher human Huxley Huxley's hydrogen hypothesis ical idea identity infinite inorganic intellectual knowledge light living lower manifestations material matter Max Schultze mechanical microscope mind molecular molecules Molluscs moral motion muscle muscular nature necessitarianism nitrogen nucleus object organic origin oxygen particles period phenomena philosophical Physiology plant plasm possess potential energy preëxisting present probably produced progress proto protoplasm qualities question reason regard relation result scientific seen species spirit structure substance syntonin temperature theory things thought tion tissue toplasm tricity truth tube vegetable vital force waves whole word