PANCREAS. 



101 



obviate the escape of the secretion through 

 a second pancreatic duct, which, he says, he 

 found very common, he closed this second 

 orifice by an ingenious method of compres- 

 sion. With this apparatus he succeeded in 

 getting a free supply of pancreatic fluid, as 

 clear as spring water, but slightly viscid, and 

 van ing in taste, from salt to acid, rough, 

 acidulo-saline, or insipid. De Graaf's memoir 

 is well worth reading, and is, considering the 

 time in which it was written, and in spite of 

 the necessary admixture of a good deal of 

 mediaeval physiology, a model of sagacious 

 forethought and patient research. He insists 

 strongly on the acidity of the fluid, not only 

 in the dog, but in man, and affirms that he 

 and many others found it to possess an acid 

 taste in a man who had been suddenly killed, 

 and whose body was still warm. But it is 

 necessary to bear in mind his coarse and 

 superficial means of examination, and the bias 

 with which he undertook his researches from 

 his strong attachment to both the physio- 

 logical and pathological views of Sylvius. 



Schuyl*, also a disciple of Sylvius, adopted 

 a process analogous to that of De Graaf, and 

 succeeded in obtaining a quantity of the 

 secretion, amounting to two or three ounces, 

 in three hours ; he pretends that what he 

 collected had an acid taste, and affirms, more- 

 over, that it coagulated milk. The researches 

 of Wepferf, Pechlin J, Brunner$, and Bohn j| 

 did not confirm the assertions of De Graaf 

 and Schuyl. These observers found the 

 pancreatic secretion turbid, whitish, not acid, 

 but having a taste slightly saline, like that of 

 lymph. Succeeding experimenters agreed no 

 better with regard to the qualities of this 

 liquid. Viridetlf said that he found it acid 

 in most animals, and pretended that it sen- 

 sibly reddened litmus. Hduermann**, on the 

 contrary, denied that it had this effect. 

 Fordyce f f found that of the dog to be co- 

 lourless, watery, and salt in taste, and affirmed 

 it to be composed of water, mucus, soda and 

 phosphorus. Meyer JJ has examined the pan- 

 creatic juice in a cat, which he found in the 

 vesicular reservoir which is sometimes met 

 with in that animal. It appeared transparent, 

 viscid, and had an alkaline taste ; it coloured 

 the mallow dye red, and red litmus paper 

 blue. Meyer says further that he found in it 

 albumen, chlorides of sodium and ammonia, 

 and a peculiar matter giving a violet pre- 

 cipitate, with chloride of tin. Lastly, Ma- 

 genclie found the pancreatic juice in a dog 

 to be yellowish, inodorous, and with a saline 

 taste. He adds that the liquid is alkaline, 



* Tractatus pro Veteri Medicina. Leyde. 1670. 

 t De Cicuta Aquatica, p. 200. 

 j De Purgantium Medic. Facult. Leyde. 1672. 

 Experiment Xova circa Pancreas. " Amst. 1C83. 

 J| Circulus Anatomico-physiologicus. Leipsig, 



De Prima Coctione, p. 266. 

 '* Physiologic, th. iii. p. 807. 



ft Versuche Uber das Verdauungsgeschaft, Leip- 

 sig, 1793. 



JJ Journ. compl. et Diet, du Sc. Me'd. t.iii. p. 283. 

 Pre'cis Ele'mentaire de Physiologie, t, ii. p. 267. 



that it coagulates with heat, and that in birds 

 it is altogether albuminous ; at least, that, ex- 

 posed to heat, it coagulates like albumen. 



With such various opinions as to the qua- 

 lities of the secretion, it is not surprising that 

 the views of its function should have been 

 discrepant, and accordingly we find that 

 many hypotheses, often far-fetched and extra- 

 vagant, were adopted to explain the part 

 which the pancreatic fluid played in digestion. 

 Some thought that it had for its destination 

 the separation of the chyle from the excre- 

 ments ; others, that it served to temper the 

 acridity of the bile; others, again, thought 

 that it diluted the chyme, or that it dissolved 

 that portion of the food which had not been 

 digested in the stomach ; that it contributed 

 to its assimilation, &c. Haller, after ex- 

 hausting himself with conjectures, can only 

 say, " Plura possunt esse officia liquoris non- 

 dum satis noti ;" and Magendie, fifty years 

 later, admits that it is impossible to say what 

 the role of the pancreatic fluid may be. 



Such, then, were the opinions expressed, or 

 rather the ignorance confessed on this subject, 

 when in 1823 the Academy of Paris proposed 

 the function of digestion as the subject of a 

 prize dissertation, and two of the essays sent 

 in, which were considered by the Academy 

 worthy of honourable mention the one by 

 Professors Tiedemann and Gmelin, and the 

 other by MM. Lenret and Lassaigne threw 

 so much additional light on the subject, and 

 furnished results which so long constituted 

 the staple of our certain knowledge of the 

 function of the pancreas, and so much of 

 which still remains unquestioned, that they 

 deserve special consideration. 



Lenret and Lassaigne, thinking that the 

 failures of recent experimenters to get any of 

 the secretion arose from the smallness of the 

 duct in the animals employed, selected the 

 horse, and succeeded in obtaining three ounces 

 in half an hour of a limpid liquid, with a slightly 

 salt taste, alkaline reaction, specific gravity 

 of 1-0026, and containing '9 per cent, of solid 

 matter. Sulphuric, nitric, and hydrochloric 

 acid slightly troubled it, and alcohol formed a 

 more abundant cloud, precipitated after a time 

 in white "flocculi ; an aqueous solution of 

 chlorine determined a light flocculent preci- 

 pitate ; infusion of gall-nuts occasioned a 

 yellowish deposit ; lastly, nitrate of silver and 

 protonitrate of mercury showed the existence 

 of chlorides, and oxalate of ammonia that of 

 lime. On treating the solid residuum with 

 alcohol and evaporating, it yielded a transpa- 

 rent viscid matter, with a salt and sharp taste, 

 the non-crystallizable portion of which con- 

 sisted of an azotised substance precipitable by 

 many metallic salts and solution of gall-nuts. 

 That portion of the residuum of the pan- 

 creatic juice which had been exhausted by 

 the alcohol was then heated with distilled 

 water, when this latter showed on evaporation 

 a certain viscosity, indicating the solution of an 

 animal principle in it. The result of the en- 

 tire qualitative analyses, the further details of 

 which I need not give, was as follows : 

 ii 3 



