298 On Animal Fluids. 



and what the author calls muco- extractive. T do not at alt 

 object to the experiments, but appeal to competent judges 

 whether it is not unjust to make this distinction. The 

 evidence of the coagnlalle matter is from the visible coagu-^ 

 lation by calorific and some re-agents ; but if there be not 

 a due proportion of it to the water in which it is dissolved, 

 such evidence is not obtainable. This may be easily proved, 

 and, as I apprehend, I have shown in my published papers, 

 by a kind of synthetic experiment. For example : serum 

 of blood, or any other known coagulable fluid, may be so 

 diluted with water as to afford no distinct proof of its pre- 

 sence by coagulation on applying calorific, although such 

 an effect may be reasonably inferred, on probat)le grounds, 

 from the disturbance of transparency or cloudiness. And 

 as far as I have found by experiment, coagulable matter so 

 diffused, on being collected by evaporation to dryness, is 

 scarcely coagulable by calorific ; so that the whole of any 

 given quantity of animal coagulal)le fluid bv such treatment 

 was rendered uncoagulable. According to my trials, too, 

 there always remained, on coagulating serum and other 

 analogous fluids, a small proportion of animal matter dis- 

 solved in the watery part, which differed in no respect from 

 the matter left on evaporating water, containing a certain 

 small or uncoagulable proportion of serum added to the 

 water, as above stated. But these dilute solutions, which 

 appear uncoagulable, denote the presence of animal matter 

 to the test of tannin. It was probably this property, and 

 the animal matter afforded by evaporation, which induced 

 some chemists to conclude that a different kind of animal 

 substance from coagulable, such as gelatinable, existed in 

 the serum of blood. Hence T conclude, that the two 

 grains of what Dr. Marcet calls inuco-cxtraclive matter, 

 afforded by 500 grains of serum after separating 44 grains of 

 albumen or coagulable matter, is this matter rendered un- 

 coagulable by dissolution. And hence too, 1 conclude, that 

 the animal matter in the other animal fluids which he ex- 

 amined, was of one kind only, viz. coagulable viatter, but 

 not demonstrable by its distinguishing property on account 

 of dissolution in a large proportion of water. 



2. Ammonia is not mentioned among the impregnating 

 ingredients. This is to me not surprisino, for it is evidently 

 from my experiment in so small a quantity as to be undis- 

 coverable in the proportions employed. If I could not 

 find by estimation above half a grain weight of it in seven or 

 eight thousand grains of animal matter, it was not likely to 

 be rendered evident in seven or eight hundred grains. 



3. Sul- 



