1865.] Organisms in Closed Vessels. 185 



person has only to examine the drawings which accompany this communi- 

 cation (in one particularly, that marked Z) in order to satisfy himself that 

 to come to any conclusion as to the presence or absence of such objects as 

 are there represented, with a magnifying power of little more than i linear 

 measurement of that from which they are drawn, would be quite impossible. 

 The Commission of the Academy of Sciences, which has not yet concluded 

 its labours, has not, so far as its present report goes, concerned itself with 

 the microscopy of the question ; it has, in fact, confined itself to the dispute 

 (which has almost become a personal one) between MM. Pasteur and 

 Pouchet. It is worth noticing, that the fact so often referred to by writers 

 on this subject, of the fluid in the closed vessels becoming cloudy or not as 

 a test of the presence or absence of bacteriums, is not satisfactory ; I have 

 constantly predicted, from the cloudiness or clearness of an infusion, the pre- 

 sence or absence of bacteriums, and very frequently been mistaken quite 

 as often too in the former case as in the latter. 



As to the conclusions which can be drawn from these experiments, I 

 need say very few words. I can now have no doubt of the fact that 

 " bacteriums" can be produced in hermetically-sealed vessels containing an 

 infusion of organic matter, whether animal or vegetable, though supplied 

 only with air passed through a red-hot tube with all necessary precautions 

 for ensuring the thorough heating of every portion of it, and though the 

 infusion itself be thoroughly boiled. But how far this fact affects the 

 question of what is called " spontaneous generation " is quite another 

 matter. 



It seems clear that either (1) the germs of bacterium are capable of 

 resisting the boiling temperature in a fluid, or (2) they are spontaneously 

 generated, or (3) they are not " organisms " at all. I was myself some- 

 what inclined to the latter belief concerning them at one time ; but some 

 researches on which I am now engaged have gone far to convince me that 

 they are really minute vegetable forms. 



The choice therefore seems to remain between the other two conclusions. 

 Upon these I will not venture a positive opinion, but remark only, that if it 

 be true that "germs" can resist the boiling temperature in fluid, then both 

 parties in the controversy are working upon a false principle, and neither M. 

 Pouchet nor M. Pasteur is likely at present to solve the question of sponta- 

 neous generation. In truth, if M. Pasteur's facts are incorrect, the whole 

 question is relegated to the domain of what the French Academy Commission 

 calls " pure discussion ;" and the one point which I claim to have established 

 by their researches is precisely that M. Pasteur's facts are inexact not 

 because his experiments were not most admirably performed, but simply 

 because the magnifying power of his microscope was insufficient for the 

 work to which he applied it. I desire to append two remarks to this 

 paper. The first is, that the common tl priori objection, which M. Pasteur 

 so well expressed in his memoir, to heterogeny in all forms, viz. that it is a 

 doctrine which has been gradually driven from all the higher forms of life 



