74 BACTERIA IN RELATION TO PLANT DISEASES. 
organism is placed in a flask or large tube. That for the other organism is placed 
inside a Chamberland filter, which is then sunk into the other receptacle, whereupon 
it is sterilized and inoculated as in the collodion-sac method. 
The favorable influence of a second organism may be studied in crossed streaks 
on sterile raw potato, carrot, turnip, etc.; on starch jelly ; or on agar, gelatin, or 
silicate jelly with addition of varying amounts of the different plant acids, or plant 
juices, or other vegetable substances.. Frost’s divided Petri dish may be used for 
the jellies. ai 
REACTION TO ANTISEPTICS AND GERMICIDES. 
- Antiseptic has been defined recently by Duclaux as follows: Any substance 
the intervention of which modifies in any form whatsoever the march of the phe- 
nomena (Bibliog., XX, Fermentation alcoolique, p. 461). ae 
I still use the word with its old primary meaning (anti, against, and sepsis, 
decay). - In this sense an antiseptic is any substance which prevents the multi- 
plication of bacteria in putrescible substances. Large doses of antiseptics often 
exert a germicidal action, but such action does not necessarily follow. Often when 
the antiseptic substance is removed or diluted beyond a certain point growth takes 
place. The first seven substances mentioned below possess very active germicidal 
powers and are antiseptic in correspondingly small doses; the remainder are more 
or less valuable antiseptics, but are not valuable germicides. 
(1.) Mercuric chloride. (5.) Lysol. ( 9.) Benzoic acid. 
(2.) Sulphate of copper. (6.) Trikresol, (10.) Salicylic acid. 
(3.) Formaldehyd (formalin). (7.) Methyl violet (Pyoktanin). (11.) Chloroform. 
- -(4.). Phenol (carbolic acid). (8.) Thymol. (12.) Sulphuric ether, 
This list may be extended indefinitely. The student should consult valuable 
digests in Sternberg’s. Text Book of Bacteriology and in Miquel & Cambier’s ‘Traité 
‘de Bactériologie. Some caution must be used in drawing conclusions from experi- 
ments. Mercuric chloride does not always destroy when the culture medium 
contains albuminoid substances. Sulphate of copper is more active in water than 
in bouillon.* ‘Some organisms will grow in a solution saturated with thymol (e.¢., 
in bouillon). Others will grow in the presence of chloroform (5 cc. of chloroform in 
test-tubes with 10 cc. of milk or beef-bouillon). ‘Ten organisms have been found by 
the writer which, under the conditions named, grew in the presence of chloroform 
and two which grew vigorously. in the presence of thymol. Russell reports one 
capable of growing in the presence of sulphuric ether. It is, therefore, not always 
safe to depend on these substances as antiseptics. Newcombe has made the same 
observation (Cellulose Enzymes, Annals of Botany, Vol. XIII, 1899, p. 60). In the 
opinion of the writer the statements of physiologists respecting the existence of 
enzymes in the tissues and fluids of the higher plants and animals must be taken 
with much allowance when chloroform, thymol, and similar antiseptics have been 
*Moore, George T., and Kellerman, Karl F. A Method of Destroying or Preventing the Growth 
of Algae and Certain Pathogenic Bacteria in Water Supplies. U.S. Department of Agriculture, 
Bureau of Plant Industry, Bulletin 64, 1904, pp. 44; see also Bull. 76, Bureau of Plant Industry. 
Certain pathogenic bacteria, such as Vibrio cholerae and Bacillus typhosus, are destroyed within a 
few hours in water containing traces of copper salts or dissolved particles of metallic copper. 
