130 AGRICULTURAL RESEARCH AND THE FARMER : 



The production of clean milk at the farm does not, however, 

 complete the story. The milk must be conveyed in churns to 

 the wholesaler and the distributor and thence, usually in small 

 cans, supplied to the consumer. If it is to reach him clean, the 

 cans and the churns must be clean, and one of the most serious 

 defects in our present system of milk distribution is the use of 

 dirty churns. A bacteriologist working at the Institute recently 

 went to the trouble of examining 500 empty milk churns on a 

 railway platform. The churns were on their way back from the 

 wholesaler to the farmers. Each churn was sampled by swilling 

 it with water free from bacteria; the swill was then submitted 

 to bacteriological analysis. It was found that only 80 of the 

 churns — out of 500 — v/ere in a usable condition. A further 140 

 were " passable " ; the remaining 280 were teeming with microbes. 

 It was further found that by the simple method of steaming the 

 churns (after washing) for three minutes sufficient bacteria 

 could be destroyed to make the churns absolutely safe 

 for all practical purposes, and that they could then be left for 

 24 hours without further treatment, provided the lids were left 

 on. This steaming method applies equally to all utensils used in 

 the cowshed or dairy. Steaming for three minutes after washing 

 makes them safe. They must not, however, be again washed 

 with ordinary cold water after steaming; other%vise organisms, 

 such as those that give rise to " ropy milk," may be introduced. 

 Tuberculosis in Dairy Cows. — Not less than thirty per cent. 

 of the milking herds of this country are affected by tubercle in 

 one form or another. Two years ago an examination was made 

 of the faeces of cows on 14 farms near Reading, and it was found 

 that four of the herds contained apparently healthy cows which 

 were excreting tubercle bacilli, and were thus a source of danger 

 to the whole herd. More recently the Institute has had a cow 

 killed which was presented to it about four years previously. 

 The post-mortem revealed a deep-seated tuberculous lesion in 

 the cow's lung. During the whole of the 4I years that it had been 

 at the Institute, although apparently healthy in every way, it 

 had been spreading the microbe of tubercle on the pasture land. 

 The difficulty in deahng with this kind of tubercle is that we 

 do not know how long the microbe lives, or what happens to it 

 when it gets on to the land. An investigation now in progress 

 at the Institute may throw some light on this. As a result of 

 the work, it has already been established that the bacilli can 

 remain alive for at least five months on pasture, for at least twelve 

 months in a dark cowshed, and for at least five months in liquid 

 manure. Whether they have really died at the end of these 

 periods, or M'hether they have been washed away or undergone a 



