ATMOSPHERIC MICROGRAPHY, 169 



species, nor is it certain that they are derived from the im- 

 mediate neighbourhood. It is very probable that several of 

 the bodies are spores of Myxogastres, the amoebae which 

 appear in certain specimens of pure rain water, being very 

 probably the mere development of Mijxogastres-s-^ores., in 

 accordance with tlie well-known observations of Prof, de Bary. 

 It would be easy to point out many which are more probably 

 referrible to Myxogastres than to any other fungi. Spores 

 of some of the higher' fungi may possibly be intermixed, 

 but their structure is in general so simple that they are not 

 easily recognized. In one instance, however, in the miscel- 

 laneous observations recorded in Section III, fig. 4, there is 

 apparently the germinating spore of Tremella or some neigh- 

 bouring genus. The extraordinary quantity of fungus spores 

 carried about by the air is very remarkable, and the more so, 

 when contrasted with Ehrenberg's observations of the dust of 

 the trade winds. 



It is necessary to take notice of some observations which 

 were made on matters contained in the air of sewers, care 

 being taken that there was no communication with the out- 

 ward air. Many years since Lord Sydney Godolphin Osborn 

 made a very praiseworthy attempt to ascertain what bodies 

 might be derived in the air from the mouths of sewers. 

 These observations were communicated to ' Household 

 Words.' It is, however, obvious, that the plan then adopted 

 would not insure the derivation from the sewer, as similar 

 bodies might be conveyed from the external air; peculiar 

 cautions, therefore, were taken to avoid this uncertainty. The 

 results were very different from the open-air observations. The 

 only spores '(Avith very few exceptions, and those far from 

 certain) which appeared, were those of Aspergillus and Peni- 

 cillium, which were developed abundantly on the walls of the 

 sewer, and these in four out of eight experiments were 

 accompanied with bacteria. Oily particles were frequent, 

 and fine molecular matter of an uncertain nature, in addition 

 to small quantities of carbonaceous and silicious particles, 

 and a few minute portions of cellular vegetable tissue. 



The following observations on the presence of bacteria 

 are important, as not opposed to the atmospheric trans- 

 mission of these organisms : — " The existence of distinct 

 bacteria in half of the specimens is also very worthy of 

 consideration when the extreme rarity of such organisms 



^ In two melted flakes of snow from Hi^ligate sent to me mounted on 

 slides many years since, there were undoubted spores of fungi, some of 

 which were possibly referrible to higher fungi. All were perfectly colourless 

 and transparent. 



