§ v.] Origin and distribution. 47 



Bacteria rank with the smallest organisms at present known 

 to us, with the least accessible and the most imperfectly investi- 

 gated. It is true that the question of actual spontaneous gene- 

 ration has been in all essential points decided in the same way 

 in their case as in that of other organisms, by the beautiful 

 researches conducted by Pasteur twenty-five years ago at the 

 instance of the Academy of Paris, and intended to test the 

 doctrine in question in connection with the smallest and least 

 accessible creatures; and every pure and trustworthy investi- 

 gation has confirmed Pasteur's results. Nevertheless there are 

 writers who still hold to the doctrine and who seek for fresh 

 arguments in support of it. A comprehensive theory in this 

 direction is contained in B^champ's doctrine of Microzymes (17) 

 published twenty years ago. The term Microzyme was applied 

 by him to minute form-elements, such as occur generally 

 in the shape of granules in the protoplasm of animals and 

 plants, and are doubtless formed in them as parts of their 

 substance. If these particles of matter are set free by any 

 cause, especially after the death of the parent, they are supposed 

 to undergo a further process of independent development and 

 to become partly Bacteria, partly also small Sprouting Fungi. 

 They not only outlive the organism which produces them, but 

 enjoy a very prolonged existence extending over geological 

 periods. Close scrutiny of the accounts given by Bdchamp in 

 a volume of almost a thousand pages shows no sharp dis- 

 crimination of forms, and no sign that the continuity of the 

 development has been strictly followed, and yet this is a point 

 of the very first importance. The whole matter therefore is 

 without any certain foundation, and is no longer a subject for 

 discussion. 



A. Wigand (18) has quite recently published a preliminary 

 communication, in which he arrives at the same results as 

 B^champ as regards the question before us. Small portions 

 of living or dead organisms, the latter not being Bacteria, are 

 said to separate from them under definite conditions and to 



