36 THEORIES OF SPONTANEOUS GENERATION 



taneous generation which is said to have occurred in the 

 experiments of one or another of the writers. However, none 

 of these experiments need be taken seriously. They are 

 amateurish and the sources of error can easily be established. 

 From the works on spontaneous generation which still 

 appear from time to time in the scientific literature, one 

 may be selected by way of an example because it concerns 

 the scientist F. Elfving, who is well known for his investiga- 

 tions in the field of microbiology. It was published in 1938 

 in the journal of the Finnish Scientific Society.'* Elfving 

 sterilised dried peas by placing them in a solution of corrosive 

 sublimate (3 : 1000) for half an hour ; he then washed them 

 with sterile water and allowed them to germinate under 

 sterile conditions in Erlenmayer flasks containing a little 

 water. When the peas grew and the sprouts had developed 

 considerably he killed them by keeping the flasks at a tem- 

 perature of 60° C for one to two hours. Some days after this 

 treatment by heat he noticed that the water in which the 

 dead plants were lying was swarming with bacteria. From 

 this experiment Elfving came to the conclusion that, in the 

 dispute between Needham and Spallanzani, it was Needham 

 who was right. The substance of the peas which had been 

 killed by gentle heating contained a special ' generative 

 power ' which gave rise to new living bacteria. It is easy 

 to detect Elfving's mistake. As was shown by investigations 

 on the production of sterile cultures of higher plants, particu- 

 larly the experiments of G. Petrov,*^ one can never success- 

 fully sterilise seeds by keeping them for this or that time in 

 a solution of corrosive sublimate. This is better achieved by 

 the action of a solution of bromine. There can be no doubt 

 that completely viable germs remained on the surfaces of 

 Elfving's peas. Elfving himself remarked that on the peas 

 " there grew mycelia which were obviously derived from 

 some spore which had survived the treatment with corrosive 

 sublimate". On repeating Elfving's experiments, using 

 bromine instead of corrosive sublimate to sterilise the peas, 

 we were easily able to convince ourselves that under these 

 conditions, as was only to be expected, no development of 

 microbes occurred. 



