372 OBSERVATIONS ON SPONTANEOUS 



puff-balls, lichens, or even the green mantle of the ruined wall, 

 were produced by spontaneous generation engendered by corrup- 

 tible matter. If the corruption of vegetables is unable to pro- 

 duce vegetable life, how can the " secretions that are inclined 

 to corruption " produce animal life ? the analogy holds to the 

 utmost rainutia. A parent of the same type is absolutely 

 required to produce the animal as well as the vegetable. It 

 is commonly said that facts are stubborn things : equivocal 

 generation has been obliged to yield to them in the vegetable 

 world, and it will no doubt soon yield to them in the animal 

 world likewise, Burmeister should also have recollected how 

 the naturalists who denied the doctrine of equivocal generation, 

 about the commencement of the last century, were puzzled to 

 account for the appearance of a quantity of parasites from the 

 pupa of a butterfly, — a fact then as triumphantly appealed to 

 by the asserters of the doctrine, as the appearance of the 

 Phthiriasis is appealed to by himself. But what was the 

 expression of Ray ? Although even with his great knowledge 

 of nature he could not give a positive explanation of it, yet 

 he sincerely declared that he thought they were produced from 

 eggs laid by a parent of the same species. In what a striking 

 view does his opinion show itself, now that it is ascertained to 

 be the fact. Equivocal generation has here been signally over- 

 thrown and vanquished. 



Burmeister does not plainly assert that the head-louse springs 

 spontaneously, because he knew that every day's experience 

 would contradict him ; and that if it could be shown that one of 

 the species described by him as generating equivocally, did 

 not originate in that manner, analogy would conclude that the 

 remaining species were generated also in the common mode. 

 I have known children to be entirely cleansed from them by 

 combing only. I have also known a dog cleansed in the same 

 manner from the lice with which it was infested ; which is a 

 plain proof that they spring not from the secretions, but from 

 individuals of the same species. Would Burmeister dare to assert 

 that the cheese-mites and the cheese-hoppers spring sponta- 

 neously (which is still the opinion of many of the vulgar) ? 

 surely not. The cheese has no vital principle to impart ; and 

 he would scarcely go the length to assert that dead matter can 

 originate a living organized being : indeed he said as much, in 

 speaking of the dead lappets of the skin that peel off; but 



