MICROSCOPIC EXAMINATIONS OF AIR. 71 



fungi and Algse. Among the rarer constituents were Acari, 

 wliich occurred in four preparations. Distinct bacteria were 

 observed in one or two instances only, and then in very small 

 numbers, but all the preparations abounded more or less in monad- 

 like molecules, and globules of an undefined nature. 



Spores and similar cells were of constant occurrence, and were 

 generally present in considerable numbers. That the majority of 

 the cells were living and ready to undergo development on 

 meeting with suitable conditions was very manifest, as in those 

 cases in which preparations were retained under observation for 

 any length of time germination rapidly took place in many of 

 the cells. In few instances did any development take place 

 beyond the formation of networks of mycelium, or masses of 

 toruloid cells, but in one or two distinct sporules were developed 

 on the filaments arising from some of the larger septate spores, 

 and in a few others JPenicillhim and Aspergillus produced their 

 characteristic heads of fructification. 



With regard to the precise nature of the spores and other cells 

 present in various instances, little can be said, as, unless their de- 

 velopment were to be carefully followed out through all its stages, 

 it is impossible to refer them to their correct species or even 

 genera. The greater number of them are apparently referable to 

 the old orders of fwngi, Sphseronemei, Melanconei, Torulacei, 

 Dematiei, and Mucedines, while some probably belonged to the 

 Puccinei and Coeomacei. Among those belonging to the Torulacei 

 the most interesting was a representative of the rare genus 

 Tetraploa. Distinct green algoid cells occurred in some specimens. 



Then follows in the report details of observations made on the 

 rise and fall of diseases, of which diarrhoea, dysentery, cholera, 

 ague, and dengue were selected, and compared with increase or 

 diminution of atmospheric cells. The conclusions arrived at are — 



" Spores and other vegetable cells are constantly present in 

 atmospheric dust, and usually occur in considerable numbers ; the 

 majority of them are living and capable of growth and deve- 

 lopment ; the amount of them present in the air appears to be 

 independent of conditions of velocity and direction of the wind ; 

 and their numbers are not diminished by moisture." 



" No connection can be traced between the numbers of bacteria, 

 spores &c , present in the air, and the occurrence of diarrhoea, 

 dysentery, cholera, ague, or dengue ; nor between the presence or 

 abundance of any special form or forms of cells, and the prevalence 

 of any of these diseases." 



" The amount of inorganic and amorphous particles and other 

 debris suspended in the atmosphere is directly dependent on 

 conditions of moisture and of velocity of wind." 



This report contains in detail a large amount of matter from 

 whence the above conclusions are drawn, and it is accompanied by 

 fourteenlarge and carefully executed plates, each containing hundreds 



