5^ Infimoria : What are tliey ? 



Artificial animal and vegetable macerations yield very 

 numerous forms, and are especially rich in the flagelliferous 

 Monads. Up to a comparatively recent date the derivation of 

 the Infusoria produced so abundantly in hay infusions has 

 been a marked subject of contention among physiologists, 

 some arguing that they were generated there spontaneously, 

 and others that they were developed from extraneously 

 derived pre-existing germs. By carefully conducted experi- 

 ments it has been my good fortune to successfully demonstrate 

 not only that the germs or spores of Infusoria abound in hay 

 previous to maceration, but also that the Infusoria which 

 produced these germs flourish in the living condition 

 in the grass previous to desiccation, remaining in a state of 

 temporary encystment during diy weather, and reawakening 

 to life with each shower of rain or fall of dew.^ 



A few concluding suggestions respecting the collection and 

 observation of Infusoria may not prove unacceptable. From 

 whatever sources samples of water containing specimens are 

 derived they should be kept separate, and have a label indi- 

 cating the place and date of collection affixed. Not only are 

 species mingled indiscriminately prone to prey upon each 

 other, but rare varieties may appear upon the scene whose 

 precise habitat cannot be successfully traced after such 

 admixture of the material collected. The student is advised 

 to habituate himself to make di-a wings, however rough, of 

 every species he encounters, placing by the side of each 

 sketch a registra,tion of its precise dimensions, taken with 

 the aid of an eye-piece micrometer. The essential structural 

 points that he should further seek to verify are the position 

 and character of the oral and excretory apertures, and 

 similar data with reference to both the contractile vesicle 

 and the nucleus or endoplast if distinctly developed. The 

 nature and distribution of the cilia or other appendages will, 

 of course, receive primary attention ; the precise number and 



3 [The whole question of biogenesis i-ersus abiogenesis is fully discussed 

 in chap. iv. of the ' Manual of the Infusoria ' ; and Mr. Kent's origina 

 and valuable observations, above alluded to, are detailed at length at 

 page 140, et seq., of the same work. — Ed.] 



