Live Stock. 



40 



[July, 1908 



ried on a splendid work, with the result 

 that it has been proved beyond doubt 

 that thousands of lives pan annually be 

 saved by rendering the milk supply 

 pure. Briefly stated, his efforts have 

 resulted in reducing the mortality 

 amongst children under five years from 

 7,451 for the ten years ending in 1896 

 to 4,965 for the ten years ending 

 in 1906. This shows a saving of 2,486 

 lives, among which were 1,554, or 62'5 

 per cent, of children under one year 

 old. It is well to mention the latter 

 fact as, during the period of life in- 

 cluded in one year, milk necessarily 

 forms the most important element in the 

 food of children. 



Such facts as we have alluded to are 

 now beyond any kind of dispute, and it 

 comes to this, that dairy farmers must 

 cither of their own free will or by the 

 force of law be compelled to provide 

 milk which will stand examination for 

 cleanliness, and also be free from disease 

 germs. This will, of course, involve a 

 very considerable alteration in the 

 practice which has obtained in dairies 

 up till now. 



The ideal system in the handling 

 of milk is that it should be pro- 

 duced under perfectly hygienic con- 

 ditions, where the byres are free 

 from dust, and where the milk can be 

 cooled to a very low temperature im- 

 mediately after being drawn from the 

 cows. The ideal, however, is next to 

 impossible in practice, as the bulk of 

 the milk consumed in our large towns is 

 necessarily produced at long distances 

 from these towns. The conclusion, 

 therefore, which the International Dairy 

 Congress arrived at, and which we have 

 already stated, namely, that milk should 

 be cooled immediately after milkintr, is 

 not possible on ordinary dairy practice- 

 WhJit, then, is the next best thing to do ? 

 There is only one possible way by which 

 milk can be rendered innocuous, and that 

 is by the application of heat, and this 

 principle is being recognised to a greater 

 extent year by year, and must ulti- 

 mately become universal. 



It is long way back to the origin of 

 the germ theory, so far back as 1675, 

 when Antony van Leeuwenhoek, a poor 

 Dutchman, a polisher of lenses, dis- 

 covered minute organisms in rain water 

 and in vegetable and animal infusions. 

 Since that time there has been a steady 

 progress in the investigation of these 

 mysterious organisms, which are only 

 -visible to the eye by means of powerful 

 microscopes. It was left, however, till 

 quite within our own day to discover 

 that milk forms a most perfect host for 

 a great variety of virulent disease germs, 



and we are indebted, as all the world 

 knows, to Pasteur for having enunciated 

 the law that heat will altogether destroy 

 these germs, We might say, however, 

 that while there are many germs which 

 find a lodgment in milk, they are not 

 necessarily all of a disease-producing or 

 pathogenic character. Many of them are 

 quite benign, the principle being, of 

 course, lactic acid. The presence of 

 lactic acid or " souring" is due to the 

 breaking up of the milk sugar, and this 

 constitutes 4| to 5 per cent, of the milk. 

 It may, therefore, be argued that if we 

 apply heat, as has been suggested, we 

 will also destroy the lactic acid bacteria, 

 and this would be a danger in itself, inas- 

 much as they act as sentinels in the 

 milk. Their presence in fresh milk serve 

 to warn the consumer that a period had 

 been reached in the age of milk at which 

 it may be described as unwholesome. It 

 is quite easy, however, to overcome this 

 objection, as lactic acid bacteria can be 

 isolated, and after Pasteurisation of the 

 milk some of these can be added to the 

 milk agaiu, so that they will be the only 

 bacterial vegetation present. 



This involve*, however, refinement of 

 dairy practice which can only be 

 attained through the education of those 

 who rjractice dairying, and it is in this 

 respect that the future practice will dffer 

 very much from the past, in consequence 

 of the admirable traiuing which is now 

 available at the various dairy institutes 

 and agricultural colleges throughout the 

 country in the theory and practice of 

 dairying. The hundreds of students 

 who are being turned out year by year 

 carry with them exact knowledge as to 

 the principles which govern the handling 

 of milk in a hygienic way, and when 

 they come to put these principles into 

 practice, we can only hope that the effect 

 will be to increase enormously the supply 

 of hygienicaily pure milk. 



It may be worth while at this point 

 just to mention briefly what the compo- 

 sition of milk is, and how it comes to 

 pass that a knowledge of its composition 

 is so essential. Cows' milk, which is the 

 commodity that we are concerned with 

 here, consists of water, fats, albuminoids, 

 or substances containing nitrogen, sugar, 

 and ash, each one of these being present 

 in pretty constant proportions. The 

 percentages may be given as follows : — 



Per cent. 



Water ... ... ... 87'25 



Fat ••• ••• ... 3*u0 



Casein ... ••• ••• 3*50 



Albumen ... ... ... O'aO 



Sugar ... ••• ... 4*50 



Ash ... ... ... 0-75 



