1 24 Oji t/i£ alkaline Matter contahied'in dropsical Fluids 



researches on the various forms of sputum nr expectorated 

 matter. I might indeed have abstained altogetlier from re- 

 ferring t') his labours; but I thought it due to him, as a 

 philosophical inquirer long known in the chemical world, 

 to point out such similarities or discordances of results as 

 occurred in our respective experiments ; thus referring the 

 mailer. to the decision of plnsiologists, and showins; that 

 there was no wish, on my side, to overlook the authority of 

 former inquuers. 



In eudeavoiiring to analyse the various objections brought 

 forward by Dr. Pearson, I am so often at a loss to under- 

 stand his meaning, and, I must add, so much embarrassed 

 by the obscure and inaccurate manner in which he has stated 

 some of my own proceedings, that it would be a task equally 

 fruitless and laborious to follow his steps closely. I must, 

 therefore, as much as possible, select those objections 

 tvhich are of a specific nature, and may be answered by an 

 appeal to experimental evidence. Such is, for instance, 

 the argument which he employs, no less than three times, 

 (once \n support of his own experiments, and twice with a 

 view to iuvaliflate mv inferences,) on the eflccts of alcohol 

 and acetic acid, — which argument is founded upon his belief 

 that acetat of soda is not soluble in alcohol, and that it is 

 7/fc^ a deliquescent salt; two palpable errors, which half a 

 grain of this salt and a few drops of alcohol, with no other 

 apparatus than a watch-glass, wonid have enabled him to 

 rectify. 



But the objection which recurs most frequently, and 

 that upon which the greatest stress is laid, is the minute- 

 ness of the quantities of saline matter subjected to experi- 

 ment. It would appear that Dr. Pearson questions whether 

 a Few grains of saline matter may be expected to yield re- 

 sults similar to those which would be obtained from larger 

 quantities ; whether, for instance, the same inferences 

 might be ilrawn from rhomboidal crystals of a minute size, 

 as from similar crystals of larger dimensions ; — or, whether 

 experiments tried upon an ounce or two of my dropsical 

 fluids, may be brouglit into competition with those which 

 he performed upon two or three pints of his ropy sputum ? 



Such a scepticism, I must own, I have myself never en- 

 tertained. I have always thought, on the contrary, that the 

 chemical [jropertics which belonged to a particle of matter 

 were exactly similar to those which would be found to be- 

 long to a whole mountain of the same substance; that a 

 rhomb of only one hundredth part of an inch might be 

 characterized by its form as distinctly as one a hundred 



times 



