552 FRAGMENTS OF SCIENCE. 



are others smitten with everlasting incompetence in regard 

 to such interpretation. To the former class in an eminent 

 degree belonged the illustrious philosopher Robert Boyle, 

 whose words in relation to this subject have in them "the 

 forecast of prophecy. "And let me add," writes Boyle in 

 his " Essay on the Pathological Part of Physik." " that he 

 that thoroughly understands the nature of ferments and 

 fermentations shall probably be much better able than he 

 that ignores them, to give a fair account of divers phe- 

 nomena of several diseases (as well fevers as others), which 

 will perhaps be never properly understood without an 

 insight into the doctrine of fermentations." 



Two hundred years have passed since these pregnant 

 words were written, and it is only in this our day that men 

 are beginning to fully realize their truth. In the domain 

 of surgery the justice of Boyle's surmise has bean most 

 strictly demonstrated. But we now pass the bounds of 

 surgery proper, and enter the domain of epidemic disease, 

 including those fevers so sagaciously referred to by Boyle. 

 The most striking analogy between &contagium and a 

 ferment is to be found in the power of indefinite self- 

 multiplication possessed and exercised by both. You 

 know the exquisitely truthful figures regarding leaven em- 

 ployed in the New Testament. A particle hid in three 

 measures of rneal leavens it all. A little leaven leaveneth 

 the whole lump. In a similar manner, a particle of 

 contagium spreads through the human body and may be so 

 multiplied as to strike down whole populations. Consider 

 the effect produced upon the system by a microscopic 

 quantity of the virus of small-pox. That virus is, to all 

 intents and purposes, a seed. It is sown as yeast is sown, 

 it grows and multiplies as yeast grows and multiplies, and 

 it always reproduces itself. To Pasteur we are indebted 

 for a series of masterly researches, wherein he exposes the 

 looseness and general baselessness of prevalent notions 

 regarding the transmutation of one ferment into another. 

 He guards himself against saying it is impossible. The 

 true investigator is sparing in the use of this word, though 

 the use of it is unsparingly ascribed to him; but, as a 

 matter of fact, Pasteur has never been able to effect the 

 alleged transmutation, while he has been always able to 

 point out the open doorways through which the affirrners 



