TRANSLOCATION OF CARBOHYDRATES 473 



The first point has been dealt with above, whilst Schimper's 

 observations upon the second were given in the first part of 

 this article. It may be added, however, that Prof. Biffen in 

 1897 made further examinations of such anatomical relations 

 and concluded that " taking all observed cases into consideration 

 . . . we may safely say that the blind endings of the latici- 

 ferous system are generally connected with the palisade cells," 

 On the other hand Kniep's studies 'led him to believe that the 

 anatomical relations do not lend any stronger support to the 

 conducting than to the protective function of the laticiferous 

 tubes. 



With regard to the third point Schimper found that only 

 in the case of Euphorbia myrsinites was there any reason to 

 suppose that the sugars passed into the laticiferous tubes ; in 

 the other species of Euphorbias with which he worked the 

 emptying proceeded just as in plants without laticiferous tubes. 

 He considered that on the whole his experimental results were 

 opposed to the theory of conduction by means of the tubes. 



The method employed in 1897 by Biffen in his work upon 

 the function of latex enabled him to obtain quantitative estima- 

 tions of the amount of sugar present under various conditions, 

 and thus afforded data of considerable significance. Unfortu- 

 nately it was not possible to carry the research beyond a certain 

 point and only a preliminary account is available. 



Latex was drawn from various species of Euphorbias and 

 after precipitation of the proteids by excess of alcohol and 

 evaporation of the filtered solution to dryness, the sugars were 

 extracted with warm water and estimated by Fehlin^'s solution. 

 Some results, expressed in terms of the sugar equivalent in 

 grams of cupric oxide per cubic centimetre of latex are given 

 below. Euphorbia pulchcrrium before darkening gave the value 

 "021, while after one day in darkness this fell to "002 — a tenth 

 of the initial value. No trace of sugar could be found after 

 another day in the dark. 



In another series of experiments the latex was examined 

 at different times on the same day, and an increase in the sugar 

 was found at the end of the afternoon thus : 



lo.o a.m. 4.0 p.m. 



•032 -049 



•030 '046 



'033 "046 



31 



