REVIEWS.

POPULAR, PHYSIOLOGY.—1. A Manual of Animal Physiology,for the use of Non-medical Students. By JOHN SHEA,M.D. London: Churchill.—2. A Manual of PopularPhysiology; being an attempt to explain the Science ofLife in Intellectual Language. By HENRY LAWSON, M.D.London: Hardwicke.

THE publication of two manuals almost simultaneously,devoted to the subject of physiology and for the instructionof unprofessional persons, is certainly a subject for congratu-lation. Of all the departments of human, knowledge whichthe recent progress of natural science has systematised andmade available for the practical use of mankind, physiologyis undoubtedly the most important. It deals with the factsand laws of life—than a knowledge of which there is nothingmore important to man. Just as he has gained a knowledgeof the conditions that influence his life, has he become morecivilised, more healthy, more moral, and more religious. Inutter ignorance of the laws of life no man can live. Thefacts with which he becomes instinctively acquainted servehim, in his barbarous and civilised state, to maintain hisexistence and even increase his race; but it is in those con-ditions of society where men are taught those laws of lifewhich are the result of sufficient investigation, that we canalone anticipate the healthiest existence and the highestmoral and religious development. It has been only withinthe present century that physiology, by embracing the sta-tistics of life and death in large communities of men, andtracing minutely, with the aid of the microscope, the minutedetails of the changes which go on in the system to producethese grand results, has been in a position to claim the atten-tion of man. It now comes forth with' an authority whichought to compel its principles to be listened to and its pre-cepts to be taught to all who have an interest in health andlife. We would here especially suggest to those who are en-

SHEA AND LAWSON, ON POPULAR PHYSIOLOGY. 2 9 1

gaged in microscopic investigations into the nature of thosechanges which go on in the tissues of the body, that theyshould make the knowledge they thus gain a3 practical aspossible. Let them not be satisfied with the beauty or theinterest of minute vital changes, but let them stride to con-nect them with the great laws of life by which the populationof the world is maintained and human health and happinesssecured. Microscopical research is not an end, and the mi-croscope is only an instrument to help the eye to investigatethe more minute phenomena of matter, in whatever form itpresents itself. Of all the practical directions in which afondness for microscopic research may be made availablefor the benefit of the individual who makes it, and for thecircle in which he moves, is that of striving to understand thelaws which regulate the healthful existence of his own body.The man who acquires any kind of knowledge at the expenseof health has made a poor exchange, and the highest use towhich human knowledge can be applied is to gain good healthand length of days. As introductions to a knowledge of thegreat laws of life which are already known, we can recommendthe manuals named above They differ in matter and style,but they have the same object in view. Dr. Shea's is a plain,straightforward account of the phenomena of life, and is theresult of much reading and reflection; Dr. Lawson is muchmore discursive, does not hesitate to introduce his own viewsof phenomena, and endeavours to amuse whilst he instructs.If we were asked for what class of readers they are adapted,we should say that Dr. Shea's manual was best adapted fora class, whilst Dr. Lawson's would be found more availablefor private reading and self-instruction. "vre will, however,endeavour to give our readers an idea of tnese useful littlebooks by extracts from those portions of the books whichtreat of microscopical subjects. We first give an extractfrom Dr. Shea's account of the blood.

" BLOOD-CORPUSCLES.—Two varieties of corpuscles exist, red andwhite. As seen under the microscope, they are flattened cells, of a cir-cular form, the red presenting either a bright or dark central spot, asthey are brought in and out of focus.

" Red corpuscles are present in large numbers in the blood; their dia-meter varies from ^ t h to jifeth of an inch, and their thickness is aboutTMisijth of an inch. When examined singly they appear almost colour-less, and it is only when viewed in numbers that they exhibit the floridcolour.

"Whitecorpuscles are much less numerous than the red, not more thanone white to fifty coloured being present in human blood. As a rule,their diameter is greater than that of the red corpuscles, and may beestimated at 5355th of an inch. The form and appearance of the cor-puscles, both red and white, varies greatly, according to the character of

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292 SHEA AND LAWSON, ON POPULAR PHYSIOLOGY.

the liquid in which they float. The colour of the blood may even bealtered by a change of form in the corpuscles. Thus it is probable thatthe difference in colour of arterial and venous blood depends on analtered form of the corpuscles contained. When subject to the actionof water, corpuscles swell, become convex, or even round, and may atlength burst.

" With regard to the structure of red blood-corpuscles, they may beconsidered to be cells, provided with an elastic cell-wall, enclosing appa-rently homogeneous contents impregnated with red colouring matter,called hsematine. The white corpuscles, however, seem to contain gra-nular matter, the cell-wall being scarcely ever visible unless the cor-puscles are treated with water or diluted acid, when the cell becomesdistended, and the wall separated from the enclosed matter.

" If the minute vessels in the web of a frog's foot are examined, bothvarieties of blood-corpuscles will be seen hurrying along in the currentof the blood, the red moving rapidly in the centre of the stream, thewhite passing more slowly along the sides of the vessels.

" The functions served by the blood-cells have not been determined,nor has it been ascertained how or where they are formed. The mostprobable source of their origin is, that they are formed from the chyleand lymph corpuscles poured into the blood from the thoracic duct; as inthe general current of the blood, corpuscles in intermediate stages ofdevelopment are always found, and indeed, occasionally the fluid in thethoracic duct has a red tinge, supposed to be due to the commencingdevelopment of hsematine in the interior of the chyle-corpuscles. Doubt-less the blood-cells are continually undergoing decay, whilst, others arebeing generated to supply their place; and most likely they are derivedin the manner just noticed, for they are proved not to be developed byfission of the pre-existing corpuscles.

" Chemically, the blood may be regarded as an alkaline fluid, com-posed principally of water, containing a certain amount of solid matter.Amongst the more important components of the solid matter, hiematinemay be mentioned. It is stated to contain iron, and is found mixed withglobuline, the compound being termed cruor.

Chemical Composition of the Shod."Water 795

I" Hsematine... 8Blood -\ ("Corpuscles ... ^ Globuline ... 140

I Iron 1

^Solidmatter J Eibrine 2Albumen : 40

|Fat 2| Salts 8(^Extractive matter 4

1000

"The difference between venous and arterial blood, as regards colour,has been already noticed; but other differences exist; thus, in the arte-rial fluid there is less albumen and more fibrine than» in the venous.Moreover, the specific gravity is lower, the amount of red corpusclesgreater, and probably, the proportion of oxygen larger in the arterialblood.

SHEA AND LAWSON, ON POPULAR PHYSIOLOGY. 2 9 3

" The quantity of blood in the body.—The precise determination of thispoint is difficult. It has been found that if numerous vessels in the bodyof an animal are opened, and the blood permitted to pour from them, a

Piles cr rouleaus of red corpus-cles, exhibiting a peculiar ten-dency tliat these corpuscles pos-sess of running together ana ad-hering by their broad surfaces.

lorpusclei

large quantity can be collected. In this manner it has been estimatedthat the weight of the blood is to that of the body :

As 1 to 12 in an ox.„ 1 to 18 in a horse.„ 1 to 16 in a dog.

These data can only be an approximation to the truth; iur uoweverfreely the vessels are opened and the blood permitted to flow, still a largequantity must remain in the body. Nor can such an experiment bemade on the human subject, except, indeed, in cases of execution. It isstated that as much as 24 lbs. of blood were taken from a decapitatedfemale. Applying the results of experiments on other animals to thehuman body, it appears that the amount of blood contained may beestimated at 18 lbs. to 20 lbs."

We now give an extract from Dr. Lawson's account of thecilia:

" The larger bronchial tubes are lined on the inside by a beautiful deli-cate down, soft as velvet, of which I have just placed a portion underthe microscope; and what a pretty sight is presented—a field of corn inminiature! This down is formed by an almost infinite number of ex-tremely minute, hair-like filaments, resting on club-shaped projections,

Tig. 40.—A portion of the lining membrane of theWindpipe, showing the Cilia, a, the club-shaped cells;S, particles of matter; c, the Cilia.—The arrows indicatethe direction of the currents.

and perpetually moving in one direction, giving exactly that appearanceto the eye which is produced by a meadow swayed in gentle undulatingcurves by the action of the wind (vide fig. 40). I now drop a small

294 DR. CHAMBERS, ON MUCUS AND PUS.

quantity of a solution of potash upon the specimen, and I have a " dis-solving view " produced, for the elegant little filaments (cilia) have van-ished.

Surely, these exquisite organisms are not without a purpose! Theremust be some office which they fulfil.

" Oh, happy living things ! No tongueTheir beauty might declare :

A spring of love gushed from my heart,And I blessed them unaware."

The cilia always move in one direction, and in the bronchial tubes thisis toward the windpipe—upwards. Hence all particles of dust, all sortsof materials in a finely powdered state, which may be accidentally suckedin during respiration, are prevented descending into and accumulatingin the air-cells by the influence of these cilia. A small, almost atomic,portion of road dust we often draw into the lungs on a blustry summer'sday, but it effects no injury, for it hardly has got in before the cilia " takeit in hand," and it is sent back again from one to the other till it hasreached the mouth.

" Were it not for this grand provision, all the millers and stonecutterswould be exterminated in a very short period. Even as it is, they domeet their death sooner than other folk, because of the inability of thecilia to prevent all the particles entering. A more energetic atom thanusual will elude their vigilance and slip down occasionally, and this beingoft repeated, the collected matter sets inflammation and other morbidprocesses agoing, which end in the extinction of life. The bronchialtubes and windpipe are composed of a kind of gristle or cartilage, mixedwith tissue of sinewy description; and in addition to these there are afew fibres of muscular tissue (flesh). These muscular filaments canhardly be seen, but a very ingenious experiment has shown us theirexistence. Muscle always contracts when galvanized, and therefore if agalvanic shock causes the lung tissue to contract, it probably containsmuscle. An English physiologist having dissected out the lung andbronchial tubes of an animal, placed the entire organ so that the openingof the windpipe was opposite the flame of a candle; next he applied thewires of the galvanic battery to the lung, and he heard the air rush out,and saw the candle extinguished."

With these extracts we must conclude our notice of thesemanuals, commending them to the notice of all who areanxious to acquire or spread a knowledge of the first prin-ciples of physiology.

Three Lectures on the Formation of Mucus and Pus, beingthe Lumleian Lectures of the Royal College of Physicians.By Dr. T. K. CHAMBERS.

THE Lumleian lectures have this year been delivered byDr. Chambers, the subject chosen being the formation ofmucus and pus. The use of the microscope is of courseessential in researches such as those which Dr. Chambers