24 FEBRUARY 1855, Page 28

TOD ON THE BLOOD.'

IF the theories of Mr. Tod should be finally established, not only would a greater revolution be effected in physiology than by Har- vey's discovery of the circulation of the blood, but the old hypothe- sis of " development," which was last brought forward in the Ves- tiges of Creation, would receive an accession of probability, though not perhaps of proof. As yet, however, we are a long way off the establishment of the theories. Many different investigators must test the observations of Mr. Tod with regard to the blood before his conclusions touching it can be received, and a much more exten- sive survey must betaken of the statistics of births and deaths than has yet been done, or perhaps than the means at present exist for doing, before the theory of the influence of the spots in the sun upon life, sex, health, sickness, and death, can rank in the Ake of things probable.

Universal conclusions of a general nature, such as the importance

• A Disquisition on certain Parts and Properties of the Blood. By David Tod. ; Author of " The Anatomy, Physiology, and Pathology of the Organ of Hearing," "An Essay on the Nature and Treatment of Hernia," &c. With illus- trative Wood-cuts. Published by Churchill. of the blood to health and life, and that we are "subject to all the cades, it is found that at birth and from birth to ten years old lnematozoa. That they are of great importance to the animal economy, may be inferred from the discoveries of Denis, who found the corpuscles [Tod's ha3matozos] to vary very greatly at different periods of life. The age of man being divided into de- ekyey influences," being put aside, as well as secondary views and numerous facts and reasonings of the nature of proofs, Mr. Tod's theory may be thus broadly stated. The small elliptical-shaped bodies detected in the blood are really animalcube of a peculiar kind ; and instead of naming them blood-globules from their shape, or blood-corpnseles from their size, it would be fitter to call them the corpuscles or Inematozoa are the fewest in number; between twenty and thirty they are most numerous; from thirty they slightly decrease till fifty, then in a greater proportion till seventy ; but they never reach so low a figure as at birth or during the first decade, and probably not as before puberty, though this table does not afford complete data as to that point. The other constituent

parts of the blood, water, fibrin, albumen, salts, &o., are omitted

in the following table. Corpuscles. Total.

At birth 3.4 100

From birth to 10 years.. 6-8 100

„ 10 — 20 „ 12.1 100

„ 20 — 30 „ ... • ....... ... 15.7 100 ,, 30 — 40 II ....... 15.2 100 ,, 40 —30 ,, 14-6 100

12.5 100 „ 50 — 60 „ 11.3 100 , 60 — 70 „

The experiments and arguments touching the constituent pro- perties of the blood, and the existence of the ha3matozoa with the consequences, are pursued into considerable detail. The subject of what the author calls "celestial influence" follows ; but the influ- ence is more properly solar heat, the spots of the sun being the ap- parent determinin‘, cause. The effect of these spots on the circum- stances which unfold and sustain life and produce death are, in Mr. Tod's opinion, various, and connected with magnetism and electri- city. From data supplied by the Registrar-General and tabularly exhibited, Mr. Tod arrives at the conclusions that the years coin- ciding with the maxima of the solar spots are the most fatal to human life, the minima most prolific ; and that the sun's magnetic influence is at the maximum when his disc exhibits the greatest number of spots. As regards number, the spots in the sun are periodical, attaining their maximum in five years and their mini- mum in other five. From statistics also furnished by the Regis- trar-General, Mr. Tod shows that the spots in the sun and the mag- netic declination appear to exercise a certain influence over deaths, births, and the proportions of males and females respectively born ; these varying periodically with the above-named phenomena. The observations, howevernre too limited, and the proportional differ- ences too small, to establish any conclusion. The facts seem rather coincident than consequent; even "cum hoc" is not " propter hoc." An hypothesis connected with generation logically follows the two theories of living animalcula3 in the blood and the wide and varied influence of solar heat. Indeed, grant the author's premises, and it will naturally follow that the number and condition of the animakulea and the " skyey influences " will considerably affect the offspring not only of man and animals but of vegetable life, to which Mr. Tod extends his theories. The idea of " development " founded on these theories is neatly and cleverly argued, perhaps the most so of anything in the book. If generation finally depends upon solar heat and its influences, any change in that heat will effect some change in living organizations according to their nature and strength. In man and the larger animals, at all events, we have no means of observation. The strength of iheir organization may resist such influence as arises under the existing constitution of things : there seems besides an instinctive reluctance to continue the propagation or even maintain the existence of what popular feeling terms monsters. In the weaker subjects of floriculture there are instances of change in what the gardener calls "sports." A flower " sports " to double, or to another colour. The careful flori- culturist treasures the seeds and sows them; some fall back to the character of the original class, but some maintain the new charac- ter, which after five generations becomes fixed. So, according to M. Fabre, the Egilops ovate takes to sporting, and in fire genera- tions becomes wheat.

"There cannot, I think, be a doubt, from what we see occurring in the vegetable kingdom, and are capable of discovering in the fossil remains of extinct animals, that every animal is in a state of progressive transition, and that all these changes are due to the variations of the earth's magnetic force for the organization of these extinct animals renders them incapable of living in air the magnetic currents of which are in accordance with the pre- sent polarity of the earth. The extinction of these animals must have been progressive ; their hrematozoa must have been gradually changed in form, size, and structure, before a corresponding change took place in their spermatozoa ; and every one of these changes must have harmonized with the variations of the earth's magnetic force. In each of these changes a cor- respondinx change in the sun's magnetic influence seems to have been the antecedent condition ; for without that influence no change in the rhyth- mical motion of the earth's magnetic force could have occurred. "Thee • assumptions lead to the following conclusions. That every radi- cal change which takes plea: in the structures of plants and animals is the

result of a series of changes ; that every one of these changes must exist for a certain period before it is succeeded by another; that in each of these ch urges a change in the rhythmical motion of the earth's magnetic force is the antecedent condition; that the polarity of the earth must be progressing slowly and incessantly towards a radical change in the daily satiation of her atmospheric magnetism ; that the plants and animals which existed at the commencement of every radical change of the earth's magnetic force

were totally different in form, size, and organization, from those which ex- isted at the beginning of the previous radical change. • • "Although we have no positive proof that the views which I entertain re-

'yarding the advent of mankind are founded on truth, we have abundance of circumstantial evidence to show that the assumption is in accordance with the immutable laws of Nature. All animals now in being were generated by and from something, and are organized in relation ; hence adapted to the present condition of the earth's magnetic force. The fossil remains of all the extinct animals hitherto discovered prove that their organization was totally different from any of the animals which exist now ; the organization of these extinct animals was, of course, in relation to the then existing condi- tion of the earth's magnetic force. The extinction of those animals pro- ceeded from a cause which must have progressively deprived them of the power of procreating their peculiar species long before the species became extinct, and that cause must have been universal ; for the extinction of one generation of animals is invariably preceded and accompanied by the pro- creation and development of another in certain fixed ratios. Their extinc- tion must therefore have been preceded and accompanied by the genera- tion of others, the organization of which coincided with the change which was slowly and progressively taking place in the condition of the earth's magnetic force. These several circumstances justify the assumption that the preceding conclusion regarding the advent of mankind is well founded."

The medical conclusions of the volume are subordinate to the physiological. Disease, according to Mr. Tod, depends upon some- thing in the blood which the exhalants have been unable to re- move. Anything, of course, which affects the life or wellbeing of the animalcules would affect the blood, and consequently the health. The dependence of epidemics either upon " celestial influence" or animalcule in the human system is by no means a new idea. It has oftener than once been broached in reference to cholera. The medical practice, as indicated in several of Mr. Tod's " cases," would seem to lead to very copious bloodletting. The literary character of A Disquisition on the Blood is mixed. Very often the composition is broad and clear, drawing closeness from the appropriate use of scientific terms. At other times the author's facts and arguments rather cloud than elucidate, and his multiplication of technical terms almost passes into pedantry. For general and indeed for professional readers who may not sit down to verify everything for themselves, the arrangement might be improved. The tabular matter and the calculations founded thereon, the physiological experiments on and the analyses of the blood, might have been treated in an appendix as separate essays, and only the broad conclusions stated in the text. On the other hand, the reader wants the story of the microscopic experiments on frogs and tadpoles, with which the work opens. He is pre- sented with the results of experiments rather than the experi- ments themselves. He has no full evidence on which to form a judgment upon the case submitted to him, and must therefore rely upon the experimenter's assertion. If the movement in the vessels of the dead subjects should arise from fermentation instead of action—from decomposition in lien of vitality—there is an end of the theory as regards the blood. The ha3matozoa fall back to corpuscles. The work exhibits a good deal of thought, and contains several suggestions on physiological and hygienic subjects worth consider- ation. There are also curious facts apart from the writer's the- ories, and some connected with the theories. Here is a combina- tion of the two.

"The moat remarkable circumstance in the history of epidemics is, that they are associated with years ending in the figures 2-3 and 7-8, more fre- quently than with those years which terminate in any other number. In 1728 and 1733 a most vehement cough seized almost all the horses about a month or two before it attacked mankind. Another epidemic raged through all Europe in 1742 and 1743. In 1758, the epidemic influenza made its ap- pearance in Scotland. In 1762, Sir George Baker notices an epidemic in- fluenza which visited almost every city in Europe. In 1767 Dr. Ileberden mentions an epidemic cold in London. In 1775, Dr. Fothergill states that the influenza appeared in the beginning of November, and that horses and dogs were much affected by the complaint. In 1782, the epidemic influenza appeared all over England. It was later in Scotland and Ireland than in England, and afterwards extended over almost all Europe. In 1788, there

was an epidemic in Paris? Vienna, Moscow, and St. Petersburg. In 1803, influenza was contagious in Edinburgh. In 1813, Bateman noticed cases re- sembling the commencement of the epidemic influenza. In 1831, cholera raged with violence in England and Scotland, and afterwards extended over Europe. In 1833, influenza was epidemic ; and likewise in 1837.

"There are other phenomena which seem to be associated with the maxima and minima of the solar spots, and the variations of the daily mag- netic declination of the earth's magnetic force, which deserve notice."

Mr. Tod might have added, that his mystic number is really present among 2.3. 7.8: add five to the two lower numbers and we reach the two higher numbers.