24 SCIENCE BULLETIN, No. 20. 



From the plates it was found that 1 c.c. of water contained 22,800 micro 

 organisms; 8,800 of these were proteolytic types, being able to liquefy 

 gelatin or digest the casein of milk. They included Bact. fluorescens 

 liquefaciens, Micrococcus flavus, Staphlococcus aureus, Bact. cloacce, a gram 

 positive bacillus and a sporing bacillus. The most conclusive proof that the 

 water was heavily contaminated with the organisms of faecal origin was the 

 presence of 6,400 per c.c. of Bact. coli. Three varieties were recognised, 

 viz., Bact. coli communis, Bact. lactis cerogenes, and Bact. cloacce, all of 

 which can cause gassy fermentation of lactose, while Bact. cloacce is also 

 able to liquefy gelatin. There were 5,200 acid and acid-coagulating 

 organisms, including 2,000 streptococci and 3,200 micrococci, while 1,400 

 other bacteria caused alkalinity or no apparent change. The 1,000 moulds 

 were species of Aspergillus, Fusarium, and Mucor. 



Atmospherically Exposed Plates. Sterile m^dia in the form of a jelly were 

 melted, and carefully poured into sterile petri dishes, and allowed to solidify. 

 These dishes were carried to the respective rooms of the factory, where the 

 lids were carefully removed, and the media exposed for 2J minutes to allow 

 the free access of micro-organisms. The media used were ordinary agar, 

 litmus lactose agar, and an acid agar specially suitable for the development 

 of moulds. 



Plate B6. An acid agar plate was exposed 2J minutes to the atmosphere 

 of the cream attemperator room ; it showed the development of nine 

 mould growths, including species of Penicillium, Alternaria and Aspergillus. 



Plate Bl. An acid agar plate exposed 2i minutes to the atmosphere 

 in the churning room showed the development of two colonies of 

 Penicillium sp. 



. Plate J53. An ordinary agar plate was exposed 2| minutes to the 

 atmosphere in the cold store room. The total micro-organisms developed 

 were twenty-one; of these, one colony was the mould Gladosporium sp., 

 while the remainder were chromogenic bacteria. 



Example No. 3. 



The best butter of this factory, after being kept for any length of time in 

 cold storage, showed evident signs of deterioration, although up to a week or 

 two after being manufactured it was of choicest quality. 



Our investigation showed that the cream as churned was of choicest grade 

 and had been well pasteurised. The infection that was in the cream before 

 being heated, although large, had not had time to develop sufficiently to affect 

 the flavour. This latent contamination was practically wiped out by the 

 system of pasteurisation employed, as was shown by the reduction of the 

 number of colonies in 1 c.c. of cream from 150,997,000 before pasteurising to 

 only 500 after the heating process had been completed. After being held 

 for nineteen hours these increased to 13,400, a striking contrast to what was 

 experienced where a similar comparison was made in the investigations 

 described in Examples Nos. 1 and 2. The increases in the present case were 

 mainly due to normal increase and the multiplication of the spore-formers 



