To the ultimate explanation of the phenomena with which he dealt he contributed nothing, and it is noteworthy in this connexion that if he did not maintain to the end of his life the corpuscular theory he never explicitly adopted the undulatory theory of light.
Sides, and (2) filled with a corpuscular N, Lateral nerves.
The pioneer work in this field, now frequently denominated " spectro-chemistry," was done by Sir Isaac Newton, who, from theoretical considerations based on his corpuscular theory of light, determined the function (n 2 - 1), where n is the refractive index, to be the expression for the refractive power; dividing this expression by the density (d), he obtained (n 2 - i)/d, which he named the " absolute refractive power."
The theoretical basis upon which this formula was devised (the corpuscular theory) was shattered early in the 19th century, and in its place there arose the modern wave theory which theoretically invalidates Newton's formula.
The blood, which is a non-corpuscular fluid, is propelled forwards by the contractile dorsal vessel and collected into the central bloodsinus; this lies over the stomochord, and is surrounded on three sides by a closed vesicle, with contractile walls, called the pericardium (Herzblase).
The perfecting of the microscope led to a full comprehension of the great doctrine of cell-structure and the establishment of the facts - (r) that all organisms are either, single corpuscles (so-called cells) of living material (microscopic animalcules, &c.) or are built up of an immense number of such units; (2) that all organisms begin their individual existence as a single unit or corpuscle of living substance, which multiplies by binary fission, the products growing in size and multiplying similarly by binary fission; and (3) that the life of a multicellular organism is the sum of the activities of the corpuscular units of which it consists, and that the processes of life must be studied in and their explanation obtained from an understanding of the chemical and physical changes which go on in each.
On light Franklin wrote to David Rittenhouse in June 1784; the sum of his own conjectures was that the corpuscular theory of Newton was wrong, and that light was due to the vibration of an elastic aether.
'The following are the more important of his works in addition to the two already mentioned: - Considerations touching the Usefulness of Experimental Natural Philosophy (1663), followed by a second part in 1671; Experiments and Considerations upon Colours, with Observations on a Diamond that Shines in the Dark (1663); New Experiments and Observations upon Cold (1665); Hydrostatical Paradoxes (1666); Origin of Forms and Qualities according to the Corpuscular Philosophy (1666); a continuation of his work on the spring of air (1669); tracts about the Cosmical Qualities of Things, the Temperature of the Subterraneal and Submarine Regions, the Bottom of the Sea, &c. with an Introduction to the History of Particular Qualities (1670); Origin and Virtues of Gems (1672); Essays of the strange Subtilty, great Efficacy, determinate Nature of Effluviums (1673); two volumes of tracts on the Saltness of the Sea, the Hidden Qualities of the Air, Cold, Celestial Magnets, Animadversions on Hobbes's Problemata de Vacuo (1674); Experiments and Notes about the Mechanical Origin or Production of Particular Qualities, including some notes on electricity and magnetism (1676); Observations upon an artificial Substance that Shines without any Preceding Illustration (1678); the Aerial Noctiluca 0680); New Experiments and Observations upon the Icy Noctiluca (1682) a further continuation of his work on the air; Memoirs for the Natural History of the Human Blood (1684); Short Memoirs for the Natural Experimental History of Mineral Waters (1685); Medicina Hydrostatica (1690); and Experimenta et Observationes Physicae (1691).