5°4 Journal of A^riculturt . [lo Aug., 1910. 



luxuriant. In dense scrub it grows little or not at all. Practically the 

 whole of the land affected by St. Jrihn's Wort in the Ovens River Vallev^ 

 would grow g(X)d Conifer timber. 



Stock will apparently eat a certain amount of the weed when it is- 

 young, but it is stated locally that it affects the flavour of mutton and 

 that cows and bullocks get a peculiar irritation of the skin when brouglit 

 on to land affected by St. John's \\'ort. The skin becomes red and in 

 extreme ca.ses peels off. causing the cattle great agony, especially in 

 summer time, when, mad with pain, they will gallop wildly through the 

 scrub. Curiously enough, the disease mainly affects white animals,* 

 whereas black, brown, or red stock suffer from it hardly at all. In varie- 

 gated animals, the irritation either begins on the white patches or is con- 

 fined to them. 



This predilection of the disease or irritation for white animals or white 

 patches on the skin, has been confirmed by personal observation, although 

 the cause of it is not easy to grasp. In addition, it is not possible 10 

 say definitely in the absence of direct experiments, whether the irritation 

 is really due to the St. John's Wort or is only accidentally connected with 

 its presence. The Hypericum oil was formerly applied externally as a 

 cure for rheumatism, and probably when continually ajjplied would pro- 

 duce an irritation of the skin. A white patch on an animal is the result 

 of the non-formation of pigment and this is presumably as.sociated with 

 the lesser vitality of the skin, as when the hair turns grey in old people. 

 This might explain why the white patches are more easily irritated. 



Poisons are quite u.seless to suppress St. John's Wort when it is deeply 

 rooted, since the doses required to kill it are not only prohibitive in cost, 

 but leave the land useless for growing other \egetation for many years.. 

 On several of the poisoned plots near Bright, nothing is growing except a 

 .scum of Algje and Moss. In others, the first plant to appear is the St. 

 John's Wort itself. The only possiljle use of a poison would be to keep 

 down the weed while cultivated land under crop rotation was temporarily 

 laid down in pasture. For this purpose, a poison is required which is. 

 cheap, easily applied and more poi.sonous to St. John's Wort than to pasture 

 plants. After testing a variety of substances, the only one which fulfilled 

 these conditions \vas found to be Phenyl. When added to water in the 

 proportion of i to 40, this forms a milky liquid readily sprayed over the 

 plants to be tested. This leaves grasses and clover unaffected but causes 

 most of the leaves of the St. John's Wort to turn brown and kills the 

 majority of the young seedlings, if a fine, evenly distributed spray is used. 

 Sorrel and other weeds are practicallv unaffected, as is also Couch grass. 

 Using a strength of one gallon of phenyl to twenty gallons of water, the 

 St. John's Wort was somewhat more strongly affected though still not 

 entirely killed ; Grass and Clover plants had their leaves slightly browned 

 and spotted. Sorrel was unaffected, Couch grass was slightly browned 

 but not permanently affected. The leaves of the Tree Tobacco showed 

 many brown spots, but were not killed. Old, deeply rooted plants of 

 St. John's Wort are merely checked by this treatment since they send up 

 fresh shoots from below. 



When infested land has been cultivated and is then laid down in 

 pasture, the St. John's Wort seedlings are at first small and grow with low 

 trailing branches more or less prostrate. If unchecked, within a year or 

 so they will ruin the pasture, but if, while they are young, the pasture is 



* Professor Gilnith informs me that white animals are more subject to such diseases as canc'er, and' 

 also to sun scald. Possibly St. John's Wort may predispose white or variegated animals to sun scald. 



