eratipn exist as in that of normal with abnormal v/ood. 



An especial class of tissue exQrescences of a ka- 

 taplastic nature, usually produced from the hark tis- 

 sue of the branches, more rarely in other places, is 

 formed by the parenchymatous , wood-like excrescences 

 occurring on the olive. (Olea europaea ) "and on the '' 

 Aleppo pine ( Pinus hale p ens is1~andr accordl-ng to the 

 unanimous statements of French and Italian authors, 

 caused by bacteria. ■»• Provided that the present state- 

 ments concerning the etiology of the swellings hold 

 true,*^ an especial significance accrues to these 

 "tumeurs a bacilles" in so far that, accordinc to our 

 present knowledge, the action of pathogenic bacteria on 

 fMnts consists chiefly in dis-organization and ne- 

 crosis and is not connected with formative stimulatory 

 (207) effects, B.esides the bacteria tubercles here named 



only those of the Leguminosae and the leaf swellings 

 on tropical 2ubiaceae observed by Zimmerman^ come into 

 •question, as exceptions to the rule* 



The bacteria galls of the olive are mostly produced 

 on branches 1 to 15 years. old, more rarely on roots, 

 leaves or fruit and indeed in such a way that, in the 

 case of branch infection, a colony of bacteria is first 

 visible near the cambium or in the bark tissue, by 

 V7hich the adjacent cells are incited to division. The 

 proliferating tissue cases the rupture of the super- 

 ficial cell layers and grows out gradually to a knot, 

 as large as 2cm. in diameter. The swellings consist 

 primarily of predominantlj thin-walled parenchyma, in 

 which are scattered thicki-v/alled cells v/ith woody and 

 pitted membra.nes. This becomes woody later and groups 

 of irregularly arranged, short-membered ducts are 

 formed, reminding one of the histology of wound-wood. 



1, Literature:- Archngeli, Sopra la Malattia de 11' olive 

 detta volgarmente "Eogna". Pisa, 1886. Savastano, Les mal- 

 adies de If oliveir et la tuberculose en particulier. C- R. 

 Acad. Sc. Paris, 1885, T. GUI, p. 1144. Savastano. Tuber- 

 culosi, Iperplasi e Tumori dell* olivo. Annuario d. R. Scuola 

 sup, d'agricolt. Portici, 1^87, ?ol. V. Pasc. IV (Therein, 

 also full literature references.) Prillieux Les tumeurs a , 

 bacillies des branches de I'o.livier et du pin d'Alep. Rev. gen. 

 Bot. 1889, T. I* p. 293. Vuillemin, Sur une bacteriocecidie 

 ou tumeur baoillaire du pin d'Alep, G. R. Acad. Sc. Paris, 

 1888, T. CVII, p. 874. Sur les relations des bacilles du 

 pin d'Al^p avec les tissus vivants. Ibid* p. 1184. 



Z, Savastano (Les maladies de I'olivier, hyperplasies et 

 tumeurs, C. R. Acad. Sc. Paris, 1836, T. UIII, p. 1278) de- 

 scribes very similar swellings on the olive which are pro- 

 duced without the participation cf any parasitic vvhatever« 



3. Ueb. Bakterienknoten in d BlSttern einiger lubiaceen. 

 Pringsheim^'s Jahrb. f. wiss. Bot.. 1901. Bd. XXXVII . p. 1. 

 Brzczinski attempted recently to trace canlrer-rlike excres- 

 cences of the apple (llectrial back to the activity of bacteria 

 (Etiologie du chancre et de la gomme des arbres frui tiers. 

 C. R* Acad. Sc. Paris, 1S02, T. CSIZV, p. 106) 



