63 On the Nature of the alkaline Matter contained in 



supposed to amount to more than a small fraction of a 

 grain ; too small for the detection of potash bv means ot 

 the plaliua soliuion, or even prohal)ly by the more sensi- 

 ble test tartaric acid, which uas not used. Yet the inge- 

 nious writer has not only inserted soda among the impreg- 

 nating ingredients of the flui(l under examination, but also 

 boldly denoted the proportion to the centesimal part of a 

 grain, i shall in another part of this connmunication, I 

 believe, demonstrate that this analysis does not warrant the 

 statement of the composition of this dropsical fluid given 

 in such precise terms : tor, on the ground of couent analogy, 

 1 cann% dv)ubt that otjeor more ingredients are present, but 

 not inquired for by experiment, nor enumerated. Hence, 

 not only is the analysis objectionable with respect to the 

 in2;redients but the proportions. It is true, in a subsequent 

 part of the investigation the deficiency seems to have been 

 perceived and acknowledged ; but if so, it vvill not be an 

 easy task to justify the publication of perhaps an inaccurate 

 analvticai statement, in opposition to my experiments which 

 have not been refuted. 



II. Of the Fluid of the Hydrocephalus intermis. 



A few grains of the saline matter of this fluid consisted 

 cf cubic crystals mixed with spicular and opake globules. 

 The .'.'ssertion is several times made, that the spicular cry- 

 stals and opake globules were carbonate of soda — that n)Ost 

 of the cubes were muriate of soda ; hut some of the snmller 

 ones were found to be muriate of potash. 'I he proofs for 

 the assertion are from the two reajieuts I emjiloycd in the 

 same inquiry ; namely, tartaric acid and platina solution 

 for the potash ; and " the carbonate of soda was identified, 

 not only by tests indicative of the absence of potash, but 

 also by its forming rhomboidal instead of prismatic cry- 

 stals, when treated with nitric acid. 



Now, I apprehend our judges vvill deem this evidence 

 unsatisfactory ; and that much more decisive proofs will 

 he reasonably expected. I beg permission to ask, whether 

 or not the laborious experinienis upon a large scale, which 

 I instituted, to exhibit evidence of the exclusive existence 

 of the potash alkali, are to be disproved by the rhomboidal 

 figure of the crystals, in place of prismatic, seen perhaps 

 only by a maKnifyina glass in the quantity of a crain or 

 two dispersed over a comparatively extensive surface; and 

 whether or not the absence of potaj^h, indicated by tests 

 operating upon minute quantities, is unequivocal evidence, 

 and ought to counterpoise experimer.ts, with quantities af- 



fordinsr 



