MICRO/YMF, TIIKOKY 7 



temperature equal to that of hot ashes without losing their life or reproductive 

 power ? " 



Pasteur called to mind this doubt of Bonnet's when he began to subject the 

 theory of spontaneous generation to experimental examination in response to 

 the offer made in 1860 by the Paris Academy of Science of a prize for "an 

 attempt, by means of suitable experiment, to throw new light on the question of 

 spontaneous generation." From the report of his researches, which appeared 

 early in the year 1862, in the form of a comprehensive treatise (I.), well 

 deserving perusal, only the most important result can be referred to here : viz., 

 the demonstration of the possibility, by the assistance of sufficiently prolonged 

 heating at an adequately high temperature, of sterilising (i.e. freeing from living 

 germs) any substance whatsoever ; and of the fact that a sample so sterilised will 

 not subsequently undergo decomposition, but will remain unaltered so long as 

 care is taken to prevent the access of germs from the external air. 



The objection raised by the heterogenists, viz., that decomposition is pre- 

 vented by the strong heating having rendered the sample unsuitable for the 

 production of germs, can be easily disposed of by inoculating the liquid with a 

 few germs these will be found to develop rapidly and luxuriantly. The sub- 

 stantiality of these germs was demonstrated by Pasteur in a very beautiful 

 experiment, for which he employed a culture vessel similar to that described by 

 H. Hoffmann (I.) in 1860, and now generally known by the name of Pasteur 

 flask ; a glass flask (fitted with a tubulus at the side for facilitating inoculation) 

 the neck of which is drawn out small and bent twice like a swan's neck. The 

 external air is obliged, in order to gain access to the contents of the bottle, to 

 pass through this neck, and as the direction of movement is changed at the first 

 bend, all the germs are deposited there. 



Thus was laid the foundation on which the edifice of Fermentation Physiology 

 was gradually raised. The possession of perfectly sterile culture media, and the 

 power of protecting them from the intrusion of unauthorised germs, is a sine qud 

 'iion for a successful and reliable study of the organisms of fermentation. 



8. Beehamp's Microzyme Theory. 



Pasteur's investigation and elucidation of the causes of the tenacity of life 

 exhibited by many germs thenceforward occupied the earnest attention of 

 mycologists, and finally led to the acknowledgment that this power of resistance 

 is possessed by the reproductive organs known as spores. The morphology and 

 physiology of these organs forms the subject of 48 to 55. At present, the only 

 point to be emphasised is that when these life-retentive organs are once killed, 

 no spontaneous development of germs can occur in the liquid harbouring them ; 

 hence such liquid will remain sterile until it is artificially re -inoculated. 



It might be supposed that the adherents of the doctrine of spontaneous 

 generation would have responded to these demonstrations by abandoning their 

 previous attitude of opposition. This, however, they did not do ; they merely 

 changed the field of combat without altering their opinion. As they could no 

 longer maintain that organised creatures could be spontaneously derived from 

 unorganised substances, they contended that the dead cells had the power of 

 liberating organised living matter capable of development into the various 

 species. 



In a subsequent paragraph we shall learn that in the cell contents of most 

 fungi, e.g. yeast, small, highly refractive bodies, known as microsomata, may be 

 frequently observed. On applying pressure to the cover -glass placed on a pre- 

 paration containing cells that exhibit such enclosures, the membranes are ruptured 

 and the microsomes are liberated.- If, now, the latter be transferred to another 



