222 THE BEGINNINGS OF LIFE. 



the same time, M. Onimus says, some of them passed 

 through the filter and were recognizable in the filtered 

 fluid. The recently effused serosity was, therefore, 

 always made use of in his subsequent experiments, 

 after he had satisfied himself that such serosity appeared 

 to be quite homogeneous and to contain no formed 

 elements of any kind 1 . Small portions of this fluid 

 were enclosed in little bags of gold-beater's skin, firmly 

 secured, and these were then inserted beneath the skin 

 of rabbits, in order to ensure the submission of the fluid 

 to the requisite temperature. The contents of the bags 

 were examined after different intervals ; and before the 

 bags were opened they were subjected to the action of 

 a full stream of water, in order to wash away every trace 

 of formed element (derived from the wounded tissues of 

 the rabbit) which might have adhered to any part of their 

 surface. When a portion of the fluid was examined 

 after the bag had remained for twelve hours beneath 



1 He ascertained, by trial with the older fluids containing leucocytes, 

 that when some of this serosity had been allowed to remain undisturbed 

 for five or six hours in a small conical glass, its upper strata had, by this 

 time, become clear, owing to the leucocytes having gravitated to the 

 narrow lower portion of the vessel. When the recent serosity however 

 was tested in the same way, he invariably found that the last drops of 

 the fluid in the bottom of the glass were quite devoid of leucocytes, and 

 indeed of all trace of solid matter, however minute. He therefore con- 

 cluded that such a fluid was really a homogeneous blastema. It must 

 be remembered, however, that exceedingly minute particles of living 

 matter less than 3 - 0( ' )()0 // in diameter might not sink in the way de- 

 scribed, and that such particles easily make their way through an 

 ordinary filter. 



