262 Agricultural Gazette of N.S.W. [April 3, 1920. 



Sample 01 — General Service Water. — The source of this water, as in tlie 

 (.ase of sample ]\\ was the head waters of a coastal river. The water was dis- 

 tributed from a conveniently positioned i-eservoir by means of the ordinary 

 system of mains and smaller pipes. Tlie sample for plating was collected 

 into a steiile vessel fi'om a tap on the cream-receiving platform. From 

 the counts, 1 c.c. of water contained 2,409 micro-organisms. Of these 

 730 were classified as gelatin liquefiers and casein digestei-s. They 

 included Bact. mycoidzs, Baot. -pyooyan^ous, Bad. fluorescens liquefaciens. 

 Bad. proeics vulgaris, and a large celled micrococcus. Of the undesirable 

 lactose fermenters five colonies of Bad. ladis (Brojenes were counted. There 

 were 300 bacteria producing acid in litmus milk, while 100 of them were 

 also able to coagulate it ; 1,230 were determined as inert, causing no change, 

 or only slight alkalinity in litmus milk in three weeks. Foi'ty-four colonies 

 of yeasts were -counted, and there were also present 100 mould growths, 

 comprising species of Penioillium Fusarium, Cladosporium, and Papuhspora. 



As noted, both waters were from the same source of supply. The difference 

 in bacterial counts might be accounted for by the fact (a) that in still waters 

 as in the case of sample iV" (butter wash water), suspended matter and 

 bacteria having weight naturally gravitate to the bottom ; {b) that a low 

 temperature is injuiious to many kinds of bacteria, even polluted waters 

 showing a marked decrease of intestinal organisms if the sample is kept cold. 



Plate (A) Demonstrating Air Infection arising from Spray of 



Polluted Water. 



A. — Poured plates of ordinary agar, litmus lactose agar and acid agai- 

 were placed on the edge of the cream-receiving vat ; the lids were removed 

 for fifteen minutes. After four days incubation, counting of the colonies 

 was commenced. 



. The totaLbacterial colonies appearing on the agar plate was 4,800. Pure 

 cultures were made of Proteus mirabilis, Bad. Jiiiorescens liqiief Miens, Bact. 

 ladis cerogenes, Oidiutn ladis, Bad. aurantiacus, and several chro5iiogenic 

 micrococci. The colonies were too thick to enable the numbers of varieties 

 to be counted. 



The acid agar plate showed a total of IGl micro-organisms; fifty-four wei^e 

 mould growths as follows: Cladosporium sp. 29; Fusarium sp, 8 ; Aspergillus 

 sp. 2 ; Penicillium .sp. 8 ; Epicoccum sp, 4 ; Alternaria sp. 3. There were 

 also counted 102 colonies of yeast and 5 B, subtilis. 



It will be noted that in this case the cream-receiving vats were adjacent 

 to the condenser tower (about 25 feet distant), the watei' flowing over which 

 was pumped from a shallow stagnant lagoon adjacent to the factory 

 premises. A favourable breeze would carry a fine spray of this polluted 

 water through the factory. Then, since the diameter of the culture plate is 

 3^ inches, into which at least 4,961 micro-organisms had fallen in fifteen 

 minutes, some idea might be gained as to the extent to which cream and 

 butter is subject to contamination with undesirable organisms from such a 

 source. 



