1873.] 



On Bacteria in Organic Infusions. 



319 



I. " Experiments on the Development of Bacteria in Organic Infu- 

 sions." By C. C. Pode, M.B., Demonstrator to the Regius 

 Professor of Medicine, and E. Ray Lankester, M.A., Fellow 

 and Lecturer of Exeter College. Communicated by Dr. 

 H. W. D. Acland, Radcliffe Librarian and Regius Professor 

 of Medicine in the University of Oxford. Received April 

 16, 1873. 



The following passage from Dr. Charlton Bastian's 'Beginnings of 

 Life' (vol. i. p. 429) induced us to make experiments similar to those 

 mentioned in it, with the view of testing the correctness of Dr. Bastian's 

 conclusion as to matter of fact : — 



" On the other hand, the labours of very many experimenters have now 

 placed it beyond all question of doubt or cavil that living Bacteria, Tor idee, 

 and other low forms of life will make their appearance and multiply within 

 hermetically-sealed flasks (containing organic infusions) which had been 

 previously heated to 212° F.. even for one or two hours. This result is 

 now so easily and surely obtainable, as to make it come within the 

 domain of natural law." And in a note is added, " In a very large 

 number of trials I have never had a single failure when an infusion of 

 turnip has been employed • and from what I have more recently seen of 

 the effects produced by the addition of a very minute fragment of cheese 

 to such an infusion (see Appendix C, pp. xxxiv-xxxvhi), I fully believe 

 that in 999 cases out of 1000, if not in every case, a positive result could 

 be obtained." Though this is one out of a great number of statements 

 made by Dr. Bastian upon which he bases speculations as to the prevalence 

 of spontaneous generation or archebiosis, we think it necessary to state 

 that we have not considered that (which is a question of interpretation) 

 as the point at issue, but merely the question of fact as to the appearance 

 of Bacteria in what may be considered, according to our present lights, 

 infusions duly guarded from inoculation. The point under discussion is 

 one as to a fact in the natural history of Bacteria, in a further study of 

 which we are occupied at the instance of the Radclrffe Trustees ; and 

 we believe that a more precise knowledge of the life-history, life-con- 

 ditions, and various forms of these organisms is necessary before the 

 hypothesis of their spontaneous generation can serve as a safe guide in 

 scientific .investigation. 



The experiments recorded below were made with infusion of hay and 

 with infusion of turnip, sometimes with the addition of a few fragments 

 of pounded cheese. It is necessary at once to call attention to three 

 precautions which we have taken, and which we think are indispensable : — 

 1. Recognizing the fact that the presence of lumps is a possible source 

 of error, we excluded these from our infusion, either by filtration or by 

 decantation. 2. To ensure the satisfactory exposure of the whole contents 



