734 'NOTES 



rapidly in the longitudinal direction, the transverse migration in that tissue being 

 often so slight as to be practically negligible. A priori, this conclusion is quite as 

 well founded as Czapek's assumption that translocation of carbohydrate takes 

 place solely in the leptome- strands. 



The above interpretation of Czapek's result is entirely in agreement with the 

 rest of our information concerning the structure and function of conducting paren- 

 chyma. The author's anatomical observations upon the connection between the 

 photosvnthetic mesophyll and the conducting parenchyma of the bundle-sheaths, 

 and Schimper's experimental results, both clearly indicate that transportation of 

 carbohydrates takes place in the parenchymatous bundle-sheaths. Czapek does not, 

 indeed, attempt to deny the truth of this statement (p. 139), but goes on to assert 

 that "from the base of the leaf-blade onwards, the entire transportation of synthetic 

 products is undertaken by the leptome-strands of the vascular bundles." But it would 

 be a very singular circumstance, if the carbohydrates which have been conveyed 

 out of the mesophyll through the parenchymatous bundle- sheaths were to depart 

 from these channels after reaching the petiole, and to pass over into the leptome- 

 strands. Tissues which are identical in structure always perform the same functions, 

 no matter where they may be located in the plant-body. Hence, the sieve-tubes of 

 the mesophyll must have exactly the same functions to perform as those in the 

 petioles and stems. If, therefore, the former are solely or principally concerned 

 with the transportation of protein materials, it is certain that the same statement 

 also applies to the latter. 



170. Hanstein : P.J. 2, 1860. In interpreting " ringing " experiments, it is 

 necessary to bear in mind the polarity of woody twigs, discovered by Vochting 

 which tends to encourage the production of roots at the basal ends of severed branches. 

 But, as Pfeffer has pointed out (Physiology, 1, p. 578), this influence of polarity does 

 not invalidate such experiments. For it is found that roots are formed abundantly 

 at the base of the long piece of each twig, and to a much smaller extent at the lower 

 end of the shorter piece. This result clearly indicates the extracambial location of 

 the protein-conducting tissues ; for, if ringing did not interfere with the conduction 

 of proteins, one would expect the greatest number of roots to appear at the lower 

 extremity of the twigs, as they do in the case of severed branches which are not 

 ringed. 



171. Ltdex-tubes. Schultz-Schultzenstein : Nova Acta, 18, Suppl. II., 1841. 

 Von Mohl : B.Z. 1843, p. 553. Unger : Ann. Wien. Mus. 2, 1840. Id. Anatomie u. 

 Physiologie d. Pflanzen, 1855, pp. 157 sqq. Aron : B.Z. 1846. Schacht : Die 

 Pflanzenzelle, etc. 1852. Id. Monatsber. Berlin. Akad. 1856. Hanstein : I.e. [167]. 

 Sachs : Experimentalphysiologie, 1865, p. 387. Trecul : Several papers in C.R, and 

 Ann. Sci. Nat., 1862-8. Dippel : Entstehung d. Milchsaftgefasse, Rotterdam, 1865. 

 David : Ub. d. Milchzellen d. Euphorb., Mor., Apoc. und Asclep. (Inaug.-Diss.), 

 Breslau, 1872. Schmalhausen : Mem. Acad. St.-Petersbg., ser. VII., 26, No. 2. 

 De Bary : Comp. Anat. pp. 183 sqq., 432 sqq., 487, 525. Faivre : Ann. Sci. Nat,, ser. 

 V., 6, 1866, pp. 33 sqq. (Ficus elastica). Id. ibid., ser. V., 10, 1869 (Morus alba). 

 Id. C.R, 88, 1879. Schullerus : Abh. Brandenburg, 24, 1882 (Euphorbia Lathyris). 

 Scott : Arb. Wiirzb. 2, p. 648. Emil Schmidt : B.Z. 1882. G. Haberlandt : Sitzb. 

 Wien, 87, 1883. Treub : Ann. Buit. 3. Schwendener : Sitzb. Berlin, 1885. A. F. W. 

 Schimper : B.Z. 1885. Chauveaud : Ann. Sci. Nat., ser. VII., 14, 1891. Kny : 

 Sitzb. Naturf. Fr. Berlin, 1893, and Zander : Bibl. Bot. No. 37, 1897 (Latex-hairs of 

 the Cichoriaceae). Chimani : Bot, Centr. 61, 1895. Molisch : Studien ub. d. Milch- 

 saft n. Schleimsaft d. Pflanzen, Jena, 1901. Gaucher : Ann. Sci. Nat., ser. VIII., 

 12, mot). Kniep : Flora, 94, 1905. Fitting: Tropenpnanzer, 13, 1909. 



