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20 HALLER 



great work on the flora of Switzerland. He returned to Berne and be- 

 gan the practice of medicine in 1729. In 1736 he was appointed pro- 

 fessor of medicine, anatomy and botany in the newly founded univer- 

 sity of Gottingen, a position v/hich he had held for 17 years. During 

 t}iis time he carried on original inve^tigat«on in botany and physiology. 

 His researches on the formation of bone, the mechanics of respiration, 

 and the development of the embryo are of the highest importance. Re- 

 garding Haller as an expositor in physiology, Foster writes : "When 

 we turn from the preceding writers on physiology and open the pages 

 of Haller's Elementa, w^e feel that we pass into modern times. Save 

 for the strangeness of most of the nomenclature, and for no small 

 differences in all that relates to the chemical changes of the body, we 

 -, seem to be reading a modem text-book of the most exhaustive kind." 

 \His chief service, however, was the careful arranging and digesting 

 ? of the theories and facts of physiology up to this time. From his time 

 physiology became an independent branch of science, to be pursued 

 for itself rather than as an adjunct to medicine. Regarding Haller's 

 method of exposition, the same writer goes on to say that "In dealing 

 with each subdivision of physiology, Haller carefully describes the 

 anatomical basis, including the data of minute structure, physical 

 properties and chemical composition, so far as these were then known. 

 He then states the observations that have been made, and in 

 respect to each question, as it arises, explains the several views 

 which have been put forward, giving minute and full references to 

 all the authors quoted, and he finally delivers a reasoned critical judg- 

 ment expounding the conclusions which may be arrived at, but not 

 omitting to state plainly when necessary the limitations which the 

 lack of adequate evidence places on forming a decided judgment. He 

 carefully recounts and as carefully criticizes all the knowledge that 

 can be gleaned about any question. If he feels unable to come to a 

 decided conclusion he candidly says so." 



But we are most concerned at present with what Haller has to 

 say on digestion. He considered saliva neutral in reaction and pos- 

 sessing no digestive properties further than the softening of food as 

 an aid to deglutition. He recognized the importance of the glandular 

 coat of the stomach, which glands he concluded furnished mucous 

 only, the true gastric juice being derived from the arteries. He also 

 concluded that pure gastric juice was neither acid nor alkaline and 

 refused to regard it as some of his predecessors had done, as a fer- 

 ment. The acidity he considered a token of the degeneration of the 

 digested food. Trituration he regards as a useful aid to digestion, es- 

 pecially where hard grains form part of the food as in birds ; but it 

 was only an aid. 



Bile, he claimed, was not a mere excrement; it was secreted by 

 the liver and stored for a time in the gall bladder, where it underwent 

 slight change. Bile is a viscid fluid, bitter but neither acid nor alka- 

 line. It has the power of dissolving fats, and so acts on a mixture 

 of oil and water as to form an emulsion. Haller considered the im- 

 portance of the pancreas due to the fact that its ducts opened into the 

 intestine in common with the bile duct ; that its fluid softened and 

 diluted the bile, thus enabling it to mix more satisfactory with the 

 food. He concluded by prophesying that there may be other func- 

 tions of pancreatic juice not well known to the physiologists of his 

 day. 



