12 



DISCOVERY 



generation before Cercidas. He directs vigorous satire 

 against the rich with their splendid houses and their 

 immense property, while " their real selves are worth 

 — three-halfpence." Two other poems attack the vice 

 of greed : " Everyone is the moneyed man's friend ; 

 if you are a rich man, even the gods will love you ; 

 but if you are poor, your own mother will hate you." 

 Here we have, even in this later age, the old virility 

 of Greek thought and its determination to cut to the 

 root of the matter. And our own generation may well 

 take to heart this splendid tradition of the Greeks, 

 their eager quest for knowledge, their burning zeal for 

 truth, their call to never-ceasing moral effort, in which 

 they found their " Medicines of Salvation." 



MAIN AUTHORITIES : PRIMARY (IN GREEK) 



The Oxyrhyncluis and oilier Papyri published for the Egypt 

 Exploration Fund by Professors Grenfell and Hunt. 



Menander (from the Cairo Papyrus). (Teubner edition by 

 Koerte, 3s. ; the Bonn edition of Kleine Texte by Sud- 

 haus, IS. dd.) 



Polyslralus, by Wilke. (Teubner, is. 6d.) 



Philodemus, Teubner volumes. 



Phnenix, by Gerhard. (Teubner, 1909 ; about gs.) 



Herondas, by Nairn. (Cambridge University Press, 12s. 6d.) 



Diogenes of CEnoanda, by William. (Teubner, 2s. 6d.) 



DERIVATIVE (IN ENGLISH) 



New Chapters in the History of Greek Literature, edited by 

 J. U. Powell and E. A. Barber. Clarendon Press, 1921, 

 I OS. (>d. 



The Problem 

 of Graft-Hybrids 



By F. E. Weiss, D.Sc, F.R.S. 



Harrison Professor of Botany in the University of Manchester 



Grafting, i.e. the insertion of a small shoot or scion 

 of one plant into a cut stem or branch of another living 

 plant with a view to their imiting, seems to have been 

 practised from time immemorial. It is said to have 

 been carried out by that wonderful and inventive 

 people, the ancient Phcenicians, and we have many 

 records from Roman times of its practice. Vines were 

 certainly grafted in those days, though for what pur- 

 pose we know not, and it was evidently thought that 

 plants quite unrelated to one another might be joined 

 by grafting, for according to Vergil {Georgics, lib. ii)— 



" Vigorous apples are grown on the barren plane, 

 A beech bears chestnuts, a mountain -ash the silver shine 

 Of pear-blossom ; under an elm have acorns been crushed 

 by swine." • 



We have, however, no experimental evidence that 

 plants differing so widely from one another as those 



' Dr. A S. Way's version. 



mentioned in the above passage can be successfully 

 grafted one upon the other. Some degree of relation- 

 ship, such as is indicated by their belonging to the 

 same Family or Natural Order, seems to be necessary 

 to enable the tissues of the two plants to unite. Thus 

 a pear can be grafted upon an apple or on a quince, but 

 not upon an ash. 



Whether in the case of a graft the stock produces 

 any change in the inserted scion or not has been a 

 subject of great controversy. If any such influence 

 were exerted by the stock, a good deal of the value of 

 the process as practised at the present day would be 

 lost, for valuable or choice forms are frequently grafted 

 on wild stock. So far only one form of transmission of 

 characters from stock to scion and vice versa has been 

 scientifically established, and that is in the case of 

 variegated plants. Shoots of plants with variegated 

 foliage are often grafted upon common green stock, and 

 the latter seems to become infected by some virus from 

 the variegated scion so that all the leaves it forms later 

 on will partake of the parti-coloured nature of the 

 stock. Most of the other cases of apparent transmission 

 of characters from stock to scion seem capable of 

 explanation by the undoubted interference with the 

 smooth passage of food-material across the line of union 

 of the two plants. 



There are, however, a few cases known of grafting 

 having been followed by the production of shoots 

 exhibiting characters intermediate between those of 

 the stock and the scion. In these cases the graft has 

 generally not succeeded, and after the inserted shoot or 

 scion has died down to the base, a bud has been formed 

 near the juncture of the two plants, and the shoot, which 

 has arisen by growing out of the bud, has presented 

 such a blending of the characters of scion and stock 

 that it has been called a graft-hybrid, and has been 

 taken to have resulted from a complete union of 

 vegetative tissues similar to that of reproductive cells. 

 This in the case of such different plants as we have 

 in stock and scion might produce a seed-hybrid. 



The first graft -hybrid recorded in scientific literature 

 is the case of the famous Bizzaria Orange grafted in 

 1644 in Florence on a Lemon stock. This remarkable 

 tree bore at the same time oranges and lemons and other 

 fruits which partook of the nature of both kinds, either 

 blended together or segregated in various ways, some, 

 indeed, having an orange shell but a lemon pulp. 



A better known instance of a graft-hybrid is that of 

 the so-called Purple Laburnum [Cytisus Adami), which 

 is very fully discussed by Darwin in Animals and 

 Plants under Domestication. This interesting plant, 

 specimens of which are now found in most botanical 

 and in many private gardens, originated in Paris in 1825 

 from an attempt to engraft the small Purple Broom 

 on the stem of the ordinary Yellow Laburnum. In 



