ASTRONOMY AND METEOROLOGY. 333 







investigations recently made. He had, for example, taken rags im- 

 ported from various countries, and shaken the dust from them into dis- 

 tilled water, which he then exposed to the atmosphere ; and after de- 

 scribing generally the character of the living forms he had discovered 

 in this pure water, he stated in detail the forms of life found in each 

 kind of dust, and among these were some new species of Rhizopoda 

 and Infusoria, and an interesting ciliated, worm-shaped form, which he 

 believed to be a collection of the larvse of some other Infusoria. The 

 general result of the microscopical examination of these fluids was as 

 follows : In the dust of Egypt, Japan, Melbourne, and Trieste, life 

 was the most abundant, and the development of the different forms 

 was rapid. In conclusion, he observed that if he was correct in sup- 

 posing the germs of the living forms that he had described to be pres- 

 ent iu the dust conveyed by the atmosphere, and in distilled water, it 

 was worthy of notice that these germs retain vitality for a lng period, 

 of which he could not pretend to define the limit. In his experiments 

 they outlived the heat of a tropical sun, and the dry ness of a warm 

 room during the whole winter ; but in Dr. Pouchet's case they re- 

 tained their life 2,000 years, for he obtained his from the interior of the 

 pyramids of Egypt, and they survived an ordeal of 400 of heat. A 

 main purpose which Mr. Samuelson had in view, was to disprove the 

 theory of spontaneous generation ; and he suggested whether the 

 great rapidity with which these germs are multiplied, might not account 

 ibr the spread of epidemic diseases. He did not profess to have any 

 acquaintance with such diseases ; but mi^ht it hot be desirable to sub- 

 ject the atmosphere of hospitals to the microscopic test ? 



Dust in the Atmosphere. - - Professor J. YTyman, of Cambridge, 

 has recently published an account of some observations made by him, 

 on the different kinds of bodies found in the dust deposited from or 

 floating in the atmosphere. The dust was obtained either from the 

 floor of an unoccupied attic, or from plates of glass covered with glyce- 

 rine and exposed to currents of air. The organic matter detected by 

 the aid of the microscope consisted of various minute fragments of veg- 

 etable tissues, such as woody-tissue, spiral-ducts, hairs, pollen, etc. A 

 few starch granules, resembling those of wheat, and giving the usual 

 reaction with iodine, were occasionally found. In the dust from an 

 attic over a frequently occupied college recitation-room, human cuti- 

 cle and epithelium scales from the mouth were detected. The lecture- 

 room and attic communicated freely by a ventilator. There were 

 also found, less frequently, however, various spherical bodies ; some of 

 them spores of cryptogamous plants, and others resembling the eggs of 

 some of the smaller "in vertebrate animals. Professor Wyman was 

 unable to identify the bodies in question, except that in one instance 

 .he detected the spores of a confervoid plant. As these were found 

 before the conferva were beginning to be developed, it is probable 

 that they came from plants of the preceding year, and had been car- 

 ried about by the winds after the drying up of the stagnant pools, in 

 the latter part of summer or autumn. Some of the egg-like bodies ap- 

 peared to contain an embryo, which could not be referred to any par- 

 ticular species. One of the spores detected was especially interesting 

 from its resemblance to pus and mucous corpuscules ; so close was the 

 resemblance that one might be readily mistaken for the other. The 



