Royal Microscopical Society. 49 



fulfilled its purpose well, was exceedingly easily managed, and 

 might, if connected with the usual meteorological instruments at 

 our observatories or other institutions, gradually enlarge our know- 

 ledge of the chances of such or such germs being either directly or 

 indirectly related to those atmospheric conditions usually associated 

 with various epidemics. The employment of this one has afforded 

 results sufficient to establish the utihty of the apparatus, which, if 

 for continued use, should by preference be made of thin sheet copper 

 or iron, enamelled on both surfaces, especially the inner one, to 

 diminish the chance under light breezes of the dust, &c., resting 

 against the inner surface in the transit of the air through the 

 instrument. Also that it should be exposed day and night, pro- 

 tected, if possible, from the rain. If found too heavy to rotate easily, 

 though, if nicely balanced, there would be little chance of this, the 

 side funnels might be omitted ; yet as the apparatus revolves some- 

 times rapidly, or in advance of the dhection of the wind, they are 

 useful. If absent, it would be almost requisite to limit the rotation 

 by a spring pressure that should be called into play according to 

 the force of the wind, so as to steady the vane more or less, yet 

 leave it free to rotate under less wind, or more gentle breezes, 

 without any hindrance. 



Note. — No attempt has been made to name the various forms gathered from 

 the air or the results obtained by their cultivation, as the abnormal conditions 

 under which they were produced might have considerably altered their common or 

 natural appearance. It has been deemed best to simply give the results in figures 

 for comparison, in case this interesting study be earnestly pursued by others ; yet 

 the absence of colour in the Plates will render even this more or less difficult, — 

 for many of the spores are so nearly of the same size and shape, though differing 

 in colour, they may easily be confounded ; also the colour of the mycelium, which 

 may help to distinguish some of the forms from each other, I found to vary con- 

 siderably with the medicine in which they were grown, so that in the absence of 

 the spore-bearing stems or heads, considerable difficulty must occur in correctly 

 naming or comparing the figures. This will furnish some apology for the few 

 allusions to the figuies in the letterpress. The chief object being to prove the 

 utility of the apparatus in the first instance. 



