TEE PROGRESS OF SCIENCE. 



93 



dissertations. The more important 

 facts and conclusions were, however, 

 collected and presented in organized 

 form in a series of lectures delivered at 

 the Institute for Experimental Medi- 

 cine. These lectures, originally pub- 

 lished in Russian, have been translated 

 into German and issued in book form 

 ('Die Arbeit der Verdauungsdriisen,' 

 Wiesbaden, 1898; J. F. Bergmann). 

 They have been widely read and have 

 received abundant praise everywhere. 

 The chief merit of Pawlow's work 

 lies in the application of new experi- 

 mental methods to the solution of im- 

 portant problems in the physiology of 

 secretion and digestion. Thus the in- 

 troduction of the combined oesophageal 

 and gastric fistulas has led to original 

 observations on the mechanism of 

 secretion; while the possibility of ob- 

 taining pure gastric juice has given 

 rise to renewed chemical investiga- 

 tion of the composition and prop- 

 erties of this secretion. By an in- 

 genious method of isolating com- 

 pletely a portion of the stomach while 

 keeping unimpaired the nerve dis- 

 tribution to the isolated part, still 

 further advances have been made. 

 Other methods have been applied by 

 Pawlow to the study of the function of 

 the pancreas and the production of the 

 bile. The specific influence of the nerv- 

 ous system on secretion, and the paths 

 along which this is exerted, have been 

 ascertained more definitely than ever 

 before. Pawlow's contributions to ex- 

 perimental technique in these depart- 

 ments of investigation are unique, and 

 their influence is already shown in the 

 renewed interest which they have 

 aroused lately in the study of digestion 

 in general. To the more purely chem- 

 ical aspects, also, this brilliant investi- 

 gator has directed his attention. A 

 prominent German physiologist has re- 

 marked that so many noteworthy re- 

 sults have not been achieved by any 

 single investigator (together with his 

 pupils) since Beaumont and Blondlot, 

 and, in more recent years, Heidenhain. 



In addition to these researches, men- 

 tion may be made of the splendid in- 

 vestigations on the seat of urea for- 

 mation in the animal body, which were 

 carried out conjointly with Professor 

 Nencki. Here again it was the applica- 

 tion of new experimental methods — the 

 Eck fistula operation, by means of 

 which direct communication is estab- 

 lished between the portal vein and the 

 vena cava in mammals — which inaugu- 

 rated a fresh series of important con- 

 tributions on the role of the liver in 

 intermediary metabolism. 



Aside from the clear analysis of the 

 problems involved and the originality 

 of the methods applied, accurate ob- 

 servation and unremitting energy 

 characterize Professor Pawlow's work. 

 Every result obtained is verified until 

 it stands as a permanent fact. Physi- 

 ologists will rejoice at the fitting recog- 

 nition which such successful achieve- 

 ments have received. 



ZINC IN DRIED FRUITS. 

 During the past few years the ex- 

 port of dried apples and other fruit 

 from this country to the continent of 

 Europe has been greatly interfered 

 with by the presence of zinc; the dis- 

 covery of traces of this metal in the 

 fruit has been deemed sufiicient ground 

 for prohibiting its importation. The 

 presence of the zinc has been accounted 

 for by the zinc trays used in the fruit 

 driers, but the abandonment of the 

 metal for this purpose has not sufficed 

 to free the fruit from suspicion. A 

 service has been rendered American 

 fruit growers by an investigation re- 

 cently carried out by Herr Soltsien, of 

 Gorlitz. He was incited to this by the 

 detection of quite a strong trace 

 (0.0067 %) of zinc in some American 

 'evaporated apples,' which had evi- 

 dently not been dried on zinc trays. He 

 finds that when zinc is present in the 

 soil or in the atmosphere, it is readily 

 taken up by plants, and, by consump- 

 tion of such contaminated vegetables 

 and fruit, even into the human body. 



