86 THE SCIENTIFIC WORK OF THE 



In tlie Eeport for 1883, Professor Stirling gives a paper on the 

 Chemistry and Histology of the Digestive Organs of Fishes,* wliich 

 contains an account of the digestive processes in the herring, 

 cod, haddock, and skate, and of the histology of the alimentary tract 

 of the herring. The reactions of the various parts of the digestive 

 canal were found to agree with those in mammals. In the herring 

 peptic extracts were obtained from the stomach ; a stronger one 

 from the crop or " cardiac sac,'^ and a weaker one from the gizzard- 

 like ''pyloric sac." The pyloric appendages yielded a tryptic fer- 

 ment, i. e. were pancreatic in function, and they probably also secrete 

 a diastatic ferment. The bile was neutral or faintly alkaline and 

 contained a diastatic ferment. In the cod and haddock the gastric 

 extract was purely peptic ; trypsin was present in the pyloric appen- 

 dages, and the bile contained a diastatic ferment. In the skate also 

 pepsin was demonstrated in the stomach, a diastatic ferment in the 

 bile, and glycogen and sugar in the liver. The histology of certain 

 portions of the digestive tract in the herring is fully described. 



The results of an elaborate research by Professor Ewart into the 

 phenomena of rigor 'mortis in fish, and its relation to putrefaction,t 

 and of another on the presence of bacteria in living fish, J have been 

 recently published. In the former the gradual onset of rigor, the 

 conditions which accelerate or retard it, and its relation to the sub- 

 sequent processes of putrefaction, are set forth in detail, and a large 

 number of experiments are desci'ibed. In the latter the occurrence 

 of bacteria in the blood and tissues of living fresh-water and marine 

 fish is described ; the causes and results of their presence being con- 

 sidered. In a third paper, § Professor Ewart goes fully into the 

 practical consequences of these researches, and gives the results of 

 his researches into the action of various reagents and processes in 

 the preservation of fish, together with many details and suggestions 

 as to the best mode of applying them in practice. 



Professor Stirling, in the Report for 1885, furnishes a paper on 

 the Red and Pale Muscles in Fishes.\\ After summarising our 

 knowledge concerning the dark and pale muscles in animals belong- 

 ing to various groups, and referring to the anatomical disposition of 

 the muscles in an osseous fish, the arrangement and microscopical 

 appearance of the red and pale muscles in the herring, whiting, 

 mackerel, haddock, and plaice are described. 



Dr. W. D. Halliburton, in the same Report, gives the results 



* Second Report, pp. 31 — 46, pis. i, ii, 1884. 



+ Proc. Roy. See, vol. xliii, p. 438, 1887. 



X Proc. Roy. Soc. Edin., 1887. 



§ The Preservation of Fish, Loudon, 1887. 



II Fourth Report, pp. 166—170, pis. iii— v, 1886. 



