60 Dairy Bacteriology. 



the common fecal inhabitant of the intestinal canal being 

 able to produce large quantities of gas.. In some cases 

 gas- generating bacteria belong to the casein- dissolving 

 group, but for the most part they attack the milk-sugar. 

 59. Slimy or ropy milk. The viscosity of milk is 

 often markedly increased as a result of bacterial fermenta- 

 tions. This condition varies much in 

 intensity, in some cases the milk 

 merely becoming viscous, when it is 

 known as sticky or slimy; then again 

 the viscosity may be so increased, that 

 particles of milk, when touched, will 

 cohere and string out in long threads, 

 in which condition it is known as 

 ropy, thready, or stringy. This con- 

 dition in milk generally occurs during 

 warm weather. Its presence prevents 

 perfect creaming, as the globules of 

 butter-fat are unable to rise, owing to 

 the viscous nature of the fluid. Nat- 

 urally it also has an injurious effect 

 upon the quality of the cream, owing 

 to the by-products that are formed. 

 While a number of different species of 

 bacteria have been more or less thor- 

 " oughly studied which possess the prop- 

 erty of rendering milk slimy, these 

 various species are not of equal im- 

 FIG. is. siimy milk. p Or tance in affecting milk under nat- 



This milk would "string * to . 



out" several feet in ural conditions. The manner in which 

 length> the slime-forming organisms are first 



introduced into milk is of considerable importance, as a 

 knowledge of this often enables restrictive measures to be 

 applied directly. Marshall 1 reports an outbreak in Michi- 

 1 Marshall, Mich. Expt. Stat., Bull. 140. 



