STUDIES ON X-AGENT

II. EFFECTS OF MATERIALS EXISTING OUTSIDE THE CULTURE MEDIA ON THE GROWTH OF PROTEUS VULGARIS

Abstract

Test tubes containing peptone solution in which Proteus vulgaris was inoculated were covered with various materials, such as water, lead, and glass, and were left in an incubator for one or two days. It was found that the growth of the bacteria was strikingly affected by the materials. The effect was observed not only when the bacterial cultures were covered by a material but also when they were located in its close proximity.
The effect appeared to be characteristic to the material, but it was found that there were factors which determined the effect more than the material. The first of such factors was the location of the material, and the second was the time at which the observation was made.
It is believed that the effect of materials upon the growth of bacteria is produced by the X-agent. The agent may be altered in some way after coming across a material, thereby a secondary agent being yielded. This secondary agent may mostly affect the bacteria placed near a material.
The effect was demonstrated in all directions around a material, but it differed with the direction.