Extraordinary Minuteness of the Irifxisoria. 32S 



idiiimals ; and views Professor Hornschuch's idea as not impro- 

 bable, that the prima germina return^ or infusoria, may be 

 formed in different bodies, under certain external influences. 

 In other respects he has followed MM. Dumas and Milne Ed- 

 wards in the doctrine of organic atoms ; and the inorganic 

 atoms, which have been of so much service to the doctrine of 

 chemical proportions, by the simple process of addition and sub- 

 traction, are more or less ideal unities, which will long continue 

 of the most decisive practical benefit to chemistry. 

 *'*' Quite recently Muncke of Heidelberg has observed the march 

 of organic bodies in infusions with a microscope of Plossel, and 

 has arrived at the result, that a passage of organized matter 

 takes place from vegetable to animal hfe, and from animal to 

 vegetable life.— (/iz>, 1831, p. 1083.) 



I must state, in the first place, that the whole range of my 

 microscopic observations are completely opposed to the prevail- 

 iiig opinion, that infusory animals or fungi can be produced by 

 simply pouring water upon dead organic substances. It must 

 be admitted that such appearances are deceiving; but when exa- 

 mined minutely, sometimes one kind of infusory animals, some- 

 times another, appear under the most similar modes of treat- 

 ment, and I have never been able to obtain certain forms by 

 means of certain infusions, although this is stated in all the ma- 

 nuals, and has succeeded with all the earlier observers. Ac- 

 cording to my results there are certain forms, but few in num- 

 ber, and these the most diffused, whose ova or individuals are 

 found in every kind of fluid, even in those of what are reckoned 

 the most poisonous parts of plants. Blainville (Diet des Soc. 

 Nat. Art. Zoophytes) has also arrived at the same opinion with 

 regard to the generatio equivoca from his own observations.' ^1 

 have often laboured in vain to produce, at will, a certain spe- 

 cies of organic bodies in little glass tubes, although in others 

 containing the same water, and situated in the same circum- 

 stances, they multiplied with the utmost profusion. 



Extraordinary Minuteness of the Infusoria. — My obsei-va- 

 tions, in regard to the smallest organic parts, have enabled ioaiei 

 to ascertain the following smallest magnitude, as actually emitt- 

 ing and discernible by the senses : 



X 2 



