34 THE SLIME OF THE HOUSEHOLD BA'JH-SPONGE, 



slime was obtained. Soap* is, therefore, out of the question as 

 a source of slime. 



The most feasible explanation is, that the substance of the 

 sponge serves as a source both of carhou and of nitrogen. It 

 consists chiefly of spongin, a proteid which contains 16 % of 

 nitrogen. This is the more pi'obable as the texture of a sponge, 

 which has been attacked, is appreciably softer after the slime has 

 been removed. 



The activity of the bacteria in ))roducing slime from sponge- 

 substance, was tested by using four sponges, one of which was 

 infected with an emulsion of Bac. i., another with Bac. ii., and a 

 third with a mixture of both, while a fourth was reserved as a 

 control. All were kept moist in covered beakers at 27°. In 

 17 days the sponge infected with Bac. ii. was a sodden, slimy 

 mass, and had shrunken considerably. The control was 

 unaffected, while the others were slightly slimy. The behaviour 

 of the sponge with the mixture of bacteria, was explained by its 

 having had a slight infection, the remains of what had not 

 been soaked up by the first sponge. Subsequently it became much 

 more slim}^ Although the experimental sponge had been 

 reduced in size and elasticity, there was no apparent change in 

 the microscopical appearance of the network; the only difl:erence 

 noted between the infected and the control sponges was that, in 

 the former, masses of bacteria-containing slime filled up the 

 spaces of the sponge. The slime from the sponge contained 

 trreat numbers of rod-forms, of various dimensions, ;ind stainin^^ 



^ If a slimy sponge is rubbed with soap, Mjueezed, and rubbed up again 

 and again, one can obtain a condition in which the sHme appears to have 

 been removed, and the sponge behaves?, to soapy water, as if no slime were 

 in it. The slime, however, has not been removed; it has simply been 

 coagulated, and the sponge will regain its slimy consistence on removal of 

 the soap with changes of fresh, soft water. A sponge which is slightly 

 slimy in hard water, becomes very slimy when soft water is used. These 

 facts show that the slime is coa,gulated by soap, and by various salts. The 

 same thing was noted when fragments of slime were inserted in nutrient 

 bouillon; they did not swell and diffuse, but appeared to become coagulated, 

 and remained in the medium as lumps of slime. 



