i 8S5- j Correspondence. 495 
increments ; and to assert that it must have been so is to 
discourage search after other, not less orderly, ways and means 
in Nature. 
Why should the odour begin and end as it did ? The period 
of its emission was shorter than had been observed in some 
previous years, when the plants may have flowered in showery 
weather, and the process of fertilisation may have required a 
longer time for its completion. In 1885 the season of flowering 
was distinguished by uninterrupted sunshine, and the flies were 
plentiful. When the ovaries were fertilised the visits of flies 
were no longer needed, and the plant ceased to emit the peculiar 
scent so alluring to them. 
^ Other plants in my garden emitting a carrion-like odour are 
Veratrum nigrum, a brown-purple Lobelia, Pothos fcetida, &c. 
The two former attract flies. Pothos is an American plant, and 
flowers too early for the help of the flies. All are of a purplish 
chocolate or livid colour, nor do I know of any really bright- 
coloured flower having the taint of carrion. To obtain the exact 
flavour of the Jargonelle pear from coal-tar the process is one of 
elimination, getting rid of the pungent elements that would 
utterly disguise the more delicate forms of sapidity. Is it pos- 
sible that plant odours may be highly compound — the perfume 
of the Jasmine, for example, being capable of being analysed 
into component elements far less grateful when taken separately? 
The elimination of a corrective constituent in the original odour 
of the Dragon Plant is more imaginable than the spontaneous 
production of such a very un-plant-like smell. I saw no special 
scent-glands, but suspect they were present on the surface of 
the spadix, which was very like that of a piece of beef after 
having been exposed for some time to the rays of the sun. 
Henry H. Higgins. 
SEWAGE TREATMENT AT CROSSNESS. 
“ But what went ye out for to see ? ” 
You will doubtless be aware that the Metropolitan Board of 
Works recently invited the London Section of the Society of 
Chemical Industry down to Crossness to see the wonderful ope- 
ration of making manganate of soda, with which the sewage of 
the Metropolis is some day to be disinfected. Had the Board 
heard all the remarks of their experienced, practical visitors, on 
the arrangement of the plant, &c,, they would not have felt highly 
flattered. 
