VENTILATION 



VENTILATION. 



was attestc-d by a bird-dealer In respect to 

 cattle, the slaughterman gave decided reasons 

 for the conclusion, that, whilst in the slaughter- 

 house, they lost their appetites and refused food, 

 1'rom the effect of the effluvium of the place, and 

 not, as was popularly supposed, from any pre- 

 sentiment of their impending fate.' 'The spread 

 of the knowledge of the fact that animals are 

 subject to typhus, consumption, and the chief 

 of the train of disorders supposed to be pecu- 

 liarly human/ remark the Commissioners in 

 another place, 'will, it may be expected, more 

 powerfully direct attention to the corrfmon means 

 of prevention.' (Report, p. 103.) 



hpizoon? diseases, are such as prevail 

 anuMiii a large number of animals at the same 

 time, just as epid'-mirs do in the human species. 

 * The epizootic are, in many respects, less serious 

 than the epidemics : nevertheless, as they often 

 affect the animals which serve for the nutriment 

 of man, and that, apart from this consideration, 

 they may have grave consequences for the puWic 

 health, they have constantly -niiai;ed the care of 

 the Council. In 1834 an fpi :,,;,, wa> reported 

 to the Administration, which prevailed amongst 

 the cows of the communes round Paris, and 

 which caused a great mortality. The researches 

 of the Council established that this ej>izootie was 

 only a chronic disease, a true pulmonary phthisis, 

 to which has been given the name of pommel t erf , 

 and by which the greater part of the cows had 

 been attacked which fill the stables of the milk- 

 men of Paris and its environs. According to 

 the Council, the principal cause of the evil was 

 to be attributed to the vicious regimen to which 

 this animal is subjected. It is known that they 

 pass a part of the year in stables perfectly closed, 

 in which the space is not proportioned to the 

 number of inmates, in which the vitiated air 

 renews itself with extreme difficulty, and in 

 which the heat is sometimes suffocating. It is 

 known, also, that they pass suddenly from the 

 food of the stable to pasture, and that in this 

 change they go from the hot and humid atmos- 

 phere of the stable to a sudden exposure to the 

 continued variations of the external air. This 

 alternation of food, and of heat and cold,opeiates 

 as a powerful cause of disease. But as the evil 

 does not announce itself in a violent manner, as 

 its progress is not very rapid, as there is even a 

 period in the disease in which the animal is dis- 

 posed to get flesh, the cow-feeder, who knows to 

 what point to keep her, sells her when she is 

 ready to calve. It is in a radius of thirty leagues 

 from the capital that cows of this kind are pur- 

 chased by the jobbers, who supply the milkmen 

 of Paris. With these last they still hold out a 

 certain number of years, if they are properly 

 cared for ; but in general they are kept in stables 

 which are neither sufficiently large nor sufficiently 

 airy, where they are exposed to the same causes 

 which gave birth to the malady. The phthisis 

 arrives insensibly at its last stage, and carries 

 off every year, from Paris and its neigbourhood, 

 a great number of these cows. 5 



" A similar discovery was only lately made as 

 to the effect of defective ventilation on the ca- 

 valry horses in some of the government barracks 

 in England ; and it is stated a saving of several 

 thousand pounds per annum was effected by an 

 easy improvement of the ventilation of the bar- 

 racks near the metropolis. An agriculturist had 

 a l.irii' 1 number of sheep housed to feed them on 

 mangel wurzel, but a great number of them 



sickened and died, and he supposed that it wag 

 the food which had killed them. A veterinary 

 surgeon, however, who happened to be aware of 

 the consequences of defective ventilation, pointed 

 out the remedy a better ventilation for the 

 over-crowded sheep. The defect was remedied ; 

 the sheep throve well." 



In adopting means for the removal or extraction 

 of foul air, in dwellings lor man, as well as in 

 stables, dairies, and even sheep-cots and pig- 

 pens, when these are made close, the ventilator, 

 or holes for its escape, should always be placed at 

 the highest part of the ceiling. Withdrawing 

 the foul air from the bottom of buildings, on the 

 supposition that, as carbonic acid gas is heavier 

 than common air, it must necessarily subside to 

 the lowest portion of the interior, though plausi- 

 ble in theory, is found to be altogether erroneous 

 in practice. For it has been ascertained that 

 this heavy gas, as it comes from the lungs 

 combined with heat and moisture, is lighter than 

 common air, as we see by the rising of the 

 breath in frosty weather. In the ventilation of 

 stables, cow-houses, &c., the supply of air will 

 require to be of larger amount than for buildings 

 intended for human beings. About 400 cubic 

 inches per minute is the usual allowance of air 

 breathed by an adult person ; but for horses and 

 cows, three times as much is required. 

 j ., The one or more openings for the escape of 

 the foul air, have their sizes or areas calculated 

 according to the following rule. Multiply the 

 number of horses the stable is to contain by 12, 

 and divide the product by 43 times the square 

 root of the height in feet from the ceiling to 

 the floor, and the quotient is the area of the ven- 

 tilation tube or tubes in feet. (Burn on Practi- 

 cal \'i nti/dtion.) 



No foul air can by any possibility be extracted 

 from the interior of a building, however well 

 arranged it may be, unless an ample supply of 

 pure air is admitted, because it is the force of 

 the entering air that causes the vitiated to be 

 expelled. 



The frcxh air should be admitted by apertures 

 in the walls, made close to the floor under each 

 window. Where this can be done, and supposing 

 there were six windows, and the fresh-air ducts 

 required to be 6 square feet, six openings should 

 be made, each equal to one square foot. All the 

 openings should have valves fixed on the outside, 

 to regulate the admission of air. In stables, 

 &c., well supplied with the means of admitting 

 fresh air and withdrawing the foul air, the doors 

 and windows may be made as tight as possible, 

 yet the interior will smell sweet and clean. 



Dairies cannot be too well supplied with 



Kure fresh air ; to secure which, they should not 

 e situated in the vicinity of any source of con- 

 tamination. (See Burn'* Treatise on Practical 

 Vtntilation* for further details.) See SOILING. 



Animal Heat. Recent researches made by 

 chemists have developed many wonderful pheno- 

 mena of life" hitherto regarded as inexplicable 

 mysteries. Among these is that relating to the 

 source of animal heat, and the kinds and propor- 

 tions of food necessary to maintain it. This 

 being a subject intimately connected with the 

 practices of sheltering and feeding cattle and 

 other stock, it of course demands the close con 

 I sideration of the intelligent farmer, to whom we 

 present the results recently obtained through the 

 | investigations of Dr. Play fair : 

 1 " The average temperature of the bodies of 



1083 



