S37 



STONE. 



STONE FOR BUILDING. 



838 



entirely destroyed, or the cells in their interior become changed, or the 

 tissue between the follicles is charged with fibrinous and other deposits. 

 This state is attended with severe dyspeptic symptoms, nausea or 

 vomiting in the morning, oppression after food, and frequently 

 an<emia and general debility. This morbid state may prevent 

 altogether the digestion of food in the stomach ; but the digestive 

 functions of the intestines may become more active, and the general 

 nutrition of the body must suffer. It is not however unfrequently 

 the case that the intestinal mucous membrane is affected in the same 

 way as the stomach, and then the general symptoms become more 

 severe. In the treatment of these cases the object should be to 

 relieve the stomach of its digestive duties as far as possible. Albu- 

 minous food should be taken in small quantities and frequently. 

 The carbonates of soda and potash may also be advantageously 

 employed so aa to facilitate the passage of the food out of the stomach 

 before digestion commences. 



C'jnyestion of the blood-vessels of the stomach occurs as the result 

 of .any mechanical impediment which prevents the blood returning from 

 the stomach towards the heart. It occurs in disease of the liver and 

 spleen, and leads to the deposit of melanic matters in the mucous 

 membrane, and to degeneration of the tissue. One of the consequences 

 of such congestion is the effusion of blood into the stomach, and its 

 ejection by vomiting. This disease is called hamatemesis. In the 

 treatment of this form of disease efforts must be made to remove its 

 causes. Astringents, as sulphuric acid, tannic acid, and acetate of lead 

 with opium may be given. Sometimes congestion of the stomach 

 occurs as the result of the suppression of some natural discharge. 



lujtamiaatlun of the stomach or gastritis is a very rare disease. 

 It is commonly seen as the result of the introduction of poisons 

 into the stomach, and also from the excessive use of alcoholic 

 beverages. When it occurs it is accompanied with congestion. It 

 is attended with vomiting, excessive thirst, and the ejection of a 

 fluid like that found in pyrosis. [PYROSIS.] In treating this form of 

 disease all stimulants must be avoided. Food of the mildest and most 

 easily digested kind must be administered, and leeches may be applied 

 to the epigastrium. Iced water and lumps of ice should also be freely 

 given. 



I 'in rat'nin of the mucous membrane of the stomach occurs both in 

 congestion and inflammation. Ulcers may however exist without the 

 y n: i itoms of these diseases. The ulcer is generally solitary, deep, well- 

 defined, of a circular or oval shape, and is about the size of a shilling. 

 It is a dangerous coudition and may end fatally by perforating the 

 membranes of the stomach, or by producing hemorrhage, or excessive 

 exhaustion. Ulceration is accompanied by pain of a gnawing and 

 burning kind a few minutes after the taking of food. There is also great 

 tenderness over the epigastrium, and frequently pain in the back. Vomit- 

 ing is also a common symptom after taking food. The treatment of 

 CMOS should be more dietetical than medicinal. Food must be taken 

 in small quantities and of the most digestible kind. Milk with prepara- 

 tions of wheaten flour are to be commended. Astringent medicines 

 should be administered, and the salts of iron may be prescribed with 

 astringents should haemorrhage supervene. 



Cancerous ulceration of the stomach is not easily distinguished from 

 simple ulcer during life, and requires the same treatment. It is not 

 so frequent as in sometimes supposed. Dr. Brinton states that not 

 more than one per cent, of fatal cases of ulceration of the stomach are 

 due to cancer. Cancerous ulceration is most frequently seated at the 

 orifices of the stomach. 



(Aitken, Uandliwk of the Science and Practice of Medicine; 

 Chambers, On Digestion and its Derangement* ; Watson, Lectures on 

 tlit. Practice uf Physic; Bennett, On the Principles and Practice of 

 ine.) 



STONE. [CALCULUS.! 



STONE FOB BUILDING. There are few practical questions 

 belonging to the building arts of more importance than those connected 

 with the nature of the stones used in them ; for not only does the 

 diameter of the architecture adopted materially depend upon the faci- 

 lities the stones present fur artistic expression, but the durability of 

 the buildings, and the retention of their original effect must be regu- 

 lated entirely by the powers of resistance of those materials to the 

 cause* of decay which are always at work upon them. Where stone of 

 large dimensions, and of great transverse strength, is used habitually, 

 architecture assumes an imposing palatial effect, with a tendency to 

 prefer the horizontal to the vertical line : where stone of small dimen- 

 sions is used, vaulted construction, heavy piers, and the minute style 

 of ornamentation (which always accompanies the use of the rendering 

 coats, almost necessarily used on such stones,) may be as distinctly 

 traced as the external characteristics of the architecture adopted ; and 

 tin; horizontal line habitually disappears in favour of the arch, or of 

 rtical line : where stones are easily worked, florid ornamentation 

 is adopted ; where they are hard, and comparatively unmanageable, 

 massive, and sometimes clumsy forms are adhered to. The durability 

 of the stones, and their capacity of supporting fine sculpture, moreover, 

 must materially affect the decision of the architect with respect to the 

 amount f decoration to be employed on them, and to the choice of 

 the mode in which they arc to be treated ; for it must evidently 

 be absurd to spend time and money on the decoration of materials 

 which are susceptible of rapid or of unequal decay. The resistances of 



stones to crushing forces have likewise a marked influence upon the 

 style of building they are capable of receiving; for that style is often 

 light, or massive, in proportion to the resistance, provided always that 

 the labour in the conversion of the stone should offer little resistance 

 to what may be called its plastic treatment. The colour of stones has 

 also an influence upon the sesthetical effect of a building ; and it, 

 therefore, becomes in its turn a matter of importance to the architect, 

 both on account of the original colour, and of its possible modi- 

 fications. 



A good building stone must possess, then, great powers of resistance 

 to crushing, and breaking, weights ; it must be even in its grain, and 

 able to furnish large blocks; it must not contain elements which 

 are susceptible of decomposition by reason of the atmospheric action 

 upon them, or of their mutual reactions upon one another ; it must be 

 non-absorbent of water, or of vapour, to a certain extent (but only to 

 a certain extent, as will be shown in the sequel); and, as far as 

 possible, be of a homogeneous nature. As a general rule, the denser 

 stones are more durable than the lighter ones ; but this law only holds 

 good when their structure is of a permanent and of a crystalline nature. 

 The stones which are of a massive character from top to bottom of the 

 quarry-bed are usually more durable than the foliated, or fissile materials 

 of the same description ; and the crystalline stones are almost always 

 superior to the amorphous ones, both in appearance and durability. 

 The granites, quartz rocks, and transition marbles furnish the most 

 lasting building stones, though even they are occasionally subject to 

 destructive actions of peculiar natures ; the sandstone conglomerates, 

 and the sandstones partially metamorphosed by the vicinity of plutonic 

 rocks, are usually more durable than the limestones ; whilst of the 

 latter, the stones presenting a regular crystallisation are far superior to 

 the saccharoid marbles, or to the amorphous earthy-textured stones. 

 The clay slates, which perhaps can hardly be considered to be building 

 stones, present singular powers of resistance to atmospheric agents, 

 after they have been exposed to the action of plutonic rocks ; and the 

 magnesian limestones, when selected from the crystalline varieties, are 

 of great practical value. When stones are mainly composed of organic 

 remains united by a more or less crystalline cement, or when they are 

 composed of materials having different rates of expansion, there are 

 great probabilities of the occurrence of rapid decay, and materials of 

 this description should be avoided for external uses. 



In the article ATMOSPHERIC INFLUENCE will be found a short review 

 of the present state of our knowledge with respect to the resistance of 

 building stones to the particular causes of decay presented by that 

 agent. There are other causes occasionally at work, however, to which 

 it may be advisable to call attention, for the stability of a building may 

 often depend on their action. Thus in bridges, it is found that some 

 stones do not satisfactorily resist exposure to tidal immersion, though 

 they may stand, as workmen say, very well when kept constantly either 

 wet or dry ; the Portland stone is an illustration of this remark. Other 

 stones again may stand well in fresh water, but they disintegrate in 

 salt water ; others may stand well in the atmosphere of the interior of 

 a country, and yet yield rapidly on the sea shore, or in certain towns. 

 Some stones resist the action of fire, such as the commonly-called fire- 

 stones of the subcretaceous series; whilst the limestones, and the 

 ordinary sandstones, are very injuriously affected by great heat ; and 

 are either partially calcined, or split and cracked by it in a manner to 

 destroy their powers of cohesion. Where the stones employed are 

 intended to receive heavy crushing loads, they must be selected from 

 amongst the denser varieties ; and the portions of the stone work 

 of a building which might take up water by capillary action must 

 be executed of such materials as should limit its range and its 

 chemical effect. And here it may be as well to remark that, although 

 in positions of this kind, the non-absorptive powers of a stone are great 

 recommendations for its use, yet that in the plain wall spaces of the 

 upper structures externally, and in floors and wall linings internally, 

 there is a disadvantage in the use of the decidedly non-absorbent 

 stones. They are in fact rapid conductors of heat, and if any moisture 

 should exist in the atmosphere it condenses on their surfaces in a 

 manner which is unsightly, and often injurious to the health of the 

 inhabitants of the building wherein this phenomenon occurs. Some 

 stones are exposed to a very disagreeable action, from the efflorescence 

 of the salts they may contain ; others again part with their consti* 

 tuents in a manner to compromise the solidity of the mass, and even 

 to produce injury to the materials around them, as for instance, in the 

 case of the magnesiau limestone, which under the action of London 

 rain parts with the sulphate of magnesia in such quantities as to 

 destroy, upon its subsequent efflorescence, the materials into which it 

 filters. It would seem, moreover, that some of the limestones are 

 liable to chemical changes of a peculiar nature ; for the marbles, 

 such as the Carrara marble, pass from the subcrystalline to the 

 saccharoid state on exposure to gentle heat, or to the effects of 

 the atmosphere ; whilst on the other hand, the Portland stone, and 

 other varieties of the carbonates of lime, which have not been affected 

 in titu by plutonic agencies, harden by exposure. It may be that in 

 the former case, the water of crystallisation evaporates ; and thus 

 allows the base to resume an amorphous character ; and that in the 

 latter, the hardening proceeds from the change in the proportions of 

 carbonic acid present, the stones being originally protocarbonates o 

 lime, and subsequently passing into the percarbonatcs. The best sand- 



