61 



the section out of the dye, drain it and place on the palm of the hand, and 

 with finger rub the surface of the section so that the superfluous fluid may 

 be removed, whilst the tubule canaliculi, &c., remain filled with the 

 solution, and mount in this condition, when the structure will be well 

 seen. To mount the section place it in the centre of the balsam on the 

 slip, then lay the cover glass on warm and gently press down, and if 

 necessary keep under pressure until the balsam sets. When the balsam 

 is bard the ^lide is ready for ringing with cement. Aspinall's enamel 

 answers admirably for this purpose, it dries quickly, and can be obtained 

 in all colours, and has also the advantage of not being afi'ected by moisture, 

 and does not leave the glass if there is any concussion. Mr. Birch 

 demonstrated how readily a section could be prepared by cutting, grinding, 

 polishing, staining, and mounting examples, and placing them under a 

 microscope. A number of members afterwai'ds joined in the work, and 

 prepared slides. 



Meeting held in the Municipal Buildings, October 20th, 1890, F. W. 

 Branson, F.I.C., F.C.S., in the chair, 



MICRO-ORGANISMS AND FOUL AIR. 

 HAROLD WAGER. 



The association of foul air with micro-organisms and disease has of late 

 years been so fully recognised, that the question of the nature of foul air 

 and the caiises which produce it becomes a most important one. The air, 

 for example, in close stuffy rooms, living rooms, concert halls, theatres, 

 and the like, is often so full of iaipurities that it becomes distinctly 

 injurious, and its efi"ects, even after two or three hours, become apparent 

 to those who breathe it, in the feeling of depression and headache, which 

 is so often produced. And it is much worse when persons have to remain 

 in the same room for several hours, perhaps day after day, for the greater 

 part of the year, for in such cases the foul air produces that paleness and 

 general ill-health so common in those who are engaged in sedentary 

 occupations. The evil effects of foul air are generally recognised to some 

 extent by everyone, but there are very few perhaps who can, or who care 

 to take the trouble of finding out of what foul air really consists, even in 

 extreme cases, and fewer still who do so where ordinary living and 

 sleeping rooms are concerned. Tlie sources of the impurities which exist 

 in air are many. Air is always full of minute suspended particles of 

 various kinds. Their numbers vary in difl"erent places, being generally 

 larger in towns and crowded districts than in villages and country places. 

 Many of these suspended particles, however, are not to be looked upon as 

 impurities ; they are of use, as pointed out by Professor Tyndall, in 

 diffusing the light in all directions in the atmosphere ; and, as pointed out 

 by Mr. Aitken, if it were not for their existence we should have no fogs 



