A UTHOKS INVESTIGA TIONS. 1 3 5 



and Drysdale may also be cavilled at as deficient of the necessary proofs, 

 inasmuch as the various species with which their researches are connected 

 are peculiar to certain putrefying animal macerations only, and cannot 

 therefore be said to fairly represent those types common to organic infusion 

 generally, with which the phenomena of de novo generation have been held 

 more especially to obtain. 



Now, among these, infusion of hay has from the earliest date of the 

 discovery of Infusoria, and the promulgation of the doctrine of spontaneous 

 generation, been recognized as the most productive material for the artificial 

 development of these minute beings, and as the one in which such presumed 

 de novo or spontaneous generation is most prominently manifested. So 

 far, this seeming special potentiality of macerated hay has not been made 

 the subject of rigid and exhaustive inquiry, while the evidence recorded 

 by Professor Tyndall concerning the extraordinary heat-resisting and in- 

 fective properties of hay-derived germs in their concrete form, is no doubt 

 accepted by the heterogenists as simply testifying to the possession by 

 this material of such potentiality. If, however, the disciples of heterogeny 

 flatter themselves that from this last uninvaded vantage-ground they may 

 peradventure be able to withstand and bring discomfiture upon the ad- 

 vancing hosts of their opponents, the panspermists, they are destined to 

 signal disappointment. 



Within the last two years the animalcules produced so abundantly in 

 hay-infusions have been the object of the author's special investigation, 

 many of the new species described in the systematic portion of this volume 

 being, indeed, the outcome of such research. Hitherto the infusorial types 

 commonly observed in hay-infusions have been of comparatively large 

 size, belonging to the higher order of the Ciliata, and pertaining to such 

 genera as Paramecium, Colpoda, Cyclidium, Oxytricha, and Vorticella. 

 These, however, represent numerically but an insignificant minority com- 

 pared with the vast hosts of flagellate forms which abound in a hay-infusion 

 during the earlier days of its maceration. In such infusions, watched from 

 day to day, and produced from hay obtained from different localities, the 

 number of types presenting themselves in tolerably regular sequence was 

 found to be perfectly marvellous. Foremost among the generic groups 

 putting in their appearance must be mentioned that of Heteromita, frequently 

 represented simultaneously by three or four species, and including more 

 especially the Heteromita (Manas) lens of O. F. Muller, H. caudata, and 

 H. gracilis. Other genera, such as Oikomonas, Dinomonas, Petalomonas, 

 Rhabdomonas, Ampkimonas, Monas proper, Cryptomonas, Hexamita, and 

 Gymnodinium, contribute likewise an almost equally considerable contin- 

 gent ; while Bacteria in their characteristic motile and quiescent states are 

 invariably present, and furnish an abundant and ever ready pabulum for 

 their more highly organized animal consociates. 



The question presented to the author for solution was, from whence 

 were derived all these myriad organisms, frequently produced in such 



