i:,i; IW. M. ('. 1 'otter. On " Baatorial 



bacillu- agin - in liquefying gelatine vei y rapidly, ami it dc<tr>y> the 

 middle lamella, and finally the cell-wall. The size of the W-terium 

 as given by Kramer is from 2'5 /x long, and 7-S/t broad, very nearly 

 the same dimensions as those of the turnip bacterium. Kramer, how- 

 ever, has not named his bacillus, and he makes no mention of the 

 Hagellura. He describes two stage* in the decay of the JX- T 

 First, tan acid stage, during which butyric acid and -ai -Innm- arid are 

 given off; in this stage the sugars, then the intercellular substance, 

 and finally the cell-walls are destroyed : the starch is not attacked. 

 Subsequently, the proteids are broken up with the formation of 

 ammonia, methylamine, trimethylamine, and other products : in this 

 stage the acids are neutralised. In the action of 7'. ikttmrfu H* \\\\\\ 

 turnips and potatoes carbonic acid is given off, and the reaction of the 

 pulp is always acid. On referring to a chemical friend, he could not 

 definitely state that butyric acid, methylamine, ami trimethylamine are 

 also produced ; he was of opinion that they were present, but that the 

 decomposition is of a more complicated nature. P. <hxtrHct<in* differs 

 from Kramer's bacillus in secreting a diastase, and always yielding an 

 acid product; further, P. ihdnictinm liquefies the gelatine in circular 

 areas, the leaf-like formation described by Kramer never having Wen 

 observed, nor have I ever found the apparently un jointed threads as 

 much as 16 /* long upon nutrient plates. Pamniel and Smith have also 

 described a Pwudoinona* (P. CMNfMfetf), which causes a "brown rot " in 

 the root and leaves of various cruciferous plants, evidently quite a 

 distinct form. 



The action of the liacteria upon the cell-wall of the higher plants 

 has been studied by several observers. Van Tieghem, probably 

 working with mixed cultures, has ascribed the destruction of cellulose 

 to Bacillus amyltibadar. Van Senus has isolated an enzyme and demon- 

 strated its solvent power upon cellulose, from two Iwcteria, one 

 anaerobic, living symbiotic-ally. Winogradsky and Fribes have 

 isolated an anaerobic bacterium which dissolves the middle lamella in 

 the process of "flax-retting," and sets free the bast fibres, without, 

 however, having any action upon the cellulose. Arthur ascril>es the 

 action of bacteria in the bacteriosis of carnations, to an en/.yme, but 

 without isolating it. 



Till quite recently I was unaware that any one had isolated from the 

 bacteria an enzyme capable of attacking the middle lamella of living 

 cells, and thus causing a plant disease. Laurent's valuable paper, 

 " Recherches Experimentales sur les Maladies des Plantes," I only 

 obtained in August of this year. It was published in Decemlier, 1898, 

 simultaneously with a preliminary paper I read at the University of 

 Durham Philosophical Society ; but previously, as early as January, 

 1898, 1 made a brief report to the Royal Society embodying the results 

 of my work, viz., the isolation of the specific bacterium causing the 



