INFLUENCES AND EFFECTS. 215 



formation 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 Penicillium 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 development 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 fungi Sphceronemei, Melanconei, 

 Torulacei, Dematiei, and Mucedines, while some probably be- 

 longed to the Pucciniei and Cocsinacei. Amongst 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 follow in the report details of obser- 

 vations made on the rise and fall of diseases, of which diarrhoea, 

 dysentery, cholera, ague, and dengue were selected and compared 

 with the increase or diminution of atmospheric cells. The con- 

 clusions 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 

 development. The amount of them present in the air appears 

 to bo independent of conditions of velocity and direction of the 

 wind, and their number is 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 velocity of wind." 



This report is accompanied by fourteen large and well-executed 

 plates, each containing hundreds of figures of organic bodies col- 

 lected from the air between February and September. It is valu- 



