ABSTRACT OF PROCEEDINGS. XXV. 



The paper on " The Mitigation of Floods in the Hunter 

 River," by J. H. Maiden, f.l.s., read 6th August, 1902, 

 was then discussed, the following gentlemen taking part : — • 

 Messrs. H. G. McKinney, J. B. Henson, O. O. Burge, H. 

 Deane, J. H. Oardew, and Dr. F. H. Quaife. Owing to the 

 lateness of the hour, the discussion was on the motion of 

 His Honor Judge Docker, adjourned to the next General 

 Monthly Meeting. 



The following is an abstract of the third Science Lecture 

 of the present session, delivered on the 28th August, by 

 R. Greig Smith, m.sc, Macleay Bacteriologist, upon "Micro- 

 organisms ; their Life and Work." 



After a reference to the universal distribution of micro- 

 organisms, the isolation of bacteria in the pure state was 

 demonstrated by lantern slides. Then followed a descrip- 

 tion of the structure, shapes and methods of growth. The 

 conditions which influence the life of bacteria such as 

 aerobiosis and anaerobiosis, lights moisture and food supply 

 were enumerated. The effect of temperature upon the 

 growth of bacteria was illustrated by the putrefaction of 

 food. The enormous multiplication of bacteria under the 

 most favourable conditions, as well as the average multi- 

 plication under ordinary circumstances was indicated. The 

 formation of spores by some bacteria was noted, and the 

 resistance of these to disinfectants and to heat introduced 

 the subject of pasteurisation and sterilisation. The various 

 methods of sterilisation including intermittent and plasmo- 

 lytic were described, and finally the action of disinfectants 

 was discussed. In the distribution of bacteria, the parts 

 played by water, air, dust, insects, and the coughing, 

 sneezing, etc., of patients were summarized. The work 

 that micro-organisms perform is made evident by the alter- 

 ation of the medium in which they subsist. The bacteria 

 of disease produce toxines, and in dealing with this branch 



