1901.] Spurge (Euphorbia hiberna, L.) on Salmonoid Fishes. 51 



pered bottle, it remains unchanged for many days, but if left open to 

 the air even for a few hours, rapid changes take place. A brownish 

 flocculent precipitate gradually takes the place of the greyish emul- 

 sion, and remains suspended for some time in the solution, which is 

 now becoming of a dark brown colour. If this solution is filtered, 

 and the filtrate again allowed to stand in the air, a precipitate again 

 forms similar to the previous one, and this process may go on for 

 weeks. 



It is obviously impossible to perform satisfactory tests upon the 

 original emulsion, and on the other hand examination of the filtrates 

 cannot be expected to give exact information with regard to the 

 original extract. Such an examination seemed necessary, however, 

 because the results obtained would throw light upon the changes the 

 extract had undergone, and reasoning from these results, the altera- 

 tions which the Spurge-extract undergoes when thrown into the rivers 

 in Ireland, might be followed. 



A minute quantity' of proteid material was detected by means of the 

 xanthoproteic, Millon's, and other tests. The presence of this proteid 

 interfered with the reactions given by other constituents of the extract, 

 but otherwise it is of no importance. Starch granules were readily 

 identified by means of iodine in the precipitate which forms in the 

 extract on standing. Glucose was identified by means of the phenyl- 

 hydrazin test, and was present in considerable quantity. 



Tannin, or some ally of tannic acid, was identified by the precipi- 

 tates given by the salts of iron and copper, as well as by various other 

 reagents. Solutions of tannic and gallic acids were then prepared in 

 varying proportions, and it was found that solutions of approximately 

 1 per cent, gave reactions similar (as to colour, quantity, and rapidity 

 of appearance of the precipitates) to those given by the aqueous 

 Spurge-extract. As the strength of the extract was about 1 gramme 

 of plant to 1 c.c. of water, it follows that the plant contains at least 

 1 per cent, of tannic acid. The percentage is probably greater than 

 this, because much tannin remains in the tissues of the plant after the 

 first filtrate is removed, and also because the presence of the proteid 

 material inhibits somewhat the reactions given by tannic acid. 



The constituents of the aqueous Spurge-extract would thus seem to 

 be: 1, proteid; 2, starch; 3, glucose; 4, resin and gum; 5, tannic 

 acid ; 6, volatile substance. 



The metals calcium, sodium, and potassium are also present, but in 

 what form was not determined. It is worthy of special notice that no 

 alkaloid was found in the latex. If the analysis just given be compared 

 with those worked out by botanists for other species of the Euphor- 

 biaceee, it will be found that E. lathyris* comes nearest to E. hiberna. 



* De Bary, ' Comparative Anatomy of the Phanerogams and Ferns,' English 

 translation, 1884, p. 184. 



