266 Brenchley.—Organic Plant Poisons . II. 
uniform, so that comparison was much facilitated. In every case the 
strongest poison,M/ioo, was almost immediately fatal,as within two days the 
roots were quite flabby and most unnaturally white, no attempt at lateral 
formation having been made. Within a week the shoots had died off in 
a way that had never been witnessed before in the greenhouse with any 
other poison, whether organic or inorganic. The stem shrivelled from 
the seed to the leaves, the whole plant was prostrate, the leaves limp and 
wilting, reminding one irresistibly of stale greens in a neglected corner of 
a greengrocer’s shop. The strongly antiseptic action of the cresol was 
shown by the fact that, in spite of the early death of the plants, no sign 
of mould growth appeared either on the plants or on the solutions during 
the six weeks that the cultures were retained in the house. 
With the next concentration, M/ioo x •§■, all the plants started alike, but 
differences manifested themselves a little later on. Within two days the tip 
of the root became constricted and white, and, except in the case of <?-cresol, 
somewhat flabby. 
With <?-cresol practically no growth was made, but for some time the 
plants continued to look healthy, as though their development had been 
merely arrested, not permanently inhibited. After about a month the 
roots became flabby, without forming any laterals. Within another fort¬ 
night the leaves began to wilt, the roots shrivelled just below the seeds so 
that the plants were unsteadily prostrate, and mould put in an appear¬ 
ance. Evidently the ^-cresol was not strong enough to prevent the latter 
phenomenon from occurring, as with the previous concentration. By the 
end of the experiment every plant was dead and shrivelled. 
With w-cresol the shoots made a considerable amount of growth, so 
that for the first month they were much better than those in ^-cresol. 
Nevertheless symptoms of degeneration set in at an earlier date, as by the 
end of the month many of the leaves were flaccid, the plants were prostrate, 
and mould formation had begun. In spite of this the plants clung to life 
more tenaciously than with the ^-cresol, and at the end of the experiment 
there were three survivors, with rather dark little roots and very small pale 
shoots, which had endeavoured to flower. 
/-Cresol at this concentration seemed, at one and the same time, to be 
more toxic than either of the others and yet to allow of greater resistance 
or recovery. A larger part of the root became flabby at an early date, the 
shoots were less well developed than any others, and a strong growth of 
mould appeared on roots and solutions within a fortnight of the start. Most 
of the plants died fairly soon, the shoots becoming flaccid and shrivelled, 
the seeds shrivelling also. The development of mould was very strong, far 
more so than with either of the other cresols. Four plants survived out of 
ten ; these possessed small shoots which had tried to flower. The roots 
were very poor, brown or black in colour, but they had tried to put out 
a few short, whitish laterals. Thus, though most of the plants were 
