July, 1911.] 



43 



Plant Sanitation. 



Metcalf and Collins, writing in 1909, 

 took a less gloomy view of the situation. 

 They believed that the spread of the 

 disease could be restricted to the badly 

 infected area, if stringent measures were 

 adopted with this object. These 

 measures included the most careful in- 

 spection of all nursery stock and tne 

 passing of very thorough quarantine 

 laws in all districts at that time 

 free from the disease. Furthermore, 

 they stated that the Department of 

 Agriculture was prepared to give all pos- 

 sible assistance, particularly in educat- 

 ing the public to recognize the disease, 

 so that trees recently infected in a pre- 

 viously healthy area could be removed, 

 and diseased parts burned. In such an 

 area, where the sources of reinfection 

 were small, very careful excision of 

 diseased parts might also prove effective. 

 Even then, they advised that constant 

 vigilance would be necessary. Spraying 

 experiments with infected trees were in- 

 conclusive. In the badly infected area, 

 the complete destruction of diseased 

 trees was recommended as the only 

 course to be adopted, since the sources of 

 reinfection were so numerous as to pre- 

 clude the possibility of successful treat- 

 ment. It was also suggested that, sub- 

 sequently, replanting with a partially 

 immune variety, such as the Japanese 

 chestnut, or with a cross between this 

 and the native species, might be found 

 possible, though the Japanese tree does 

 not yield such good nuts, and does not 

 appear to be as nearly as useful as 

 lumber. 



No disease as destructive as this has 

 ever yet been experienced in the West 

 Indies. The sugar industry was fortun- 

 ately saved by the discovery of com- 

 paratively immune varieties of cane, 

 giving returns as good as, or even better 

 than, the variety destroyed. Neverthe- 

 less, the experience of the United States 

 in the instance quoted indicates that an 

 outbreak of disease might occur on any 

 crop, which could not be checked by the 

 most skilful treatment or the most 

 thorough co-operation, and that noth- 

 ing would remain but to face the conse- 

 quences and to adopt the cultivation of 

 some different plant. 



CHEMICAL PROCESS TO PRESERVE 

 TIMBER. 



Wood Boiled in Saccharine Solution 

 —Process Claimed to be Simple 

 and Inexpensive. 



(Prom the Manila Bulletin, June 5, 1911.) 



A limited stock company, located near 

 Wellington, New Zealand, is now engaged 

 in treating chemically lumber of ordin- 



ary quality for railroad ties, fence posts, 

 etc., and claim is made that the mate- 

 rial so treated will last as long as the 

 best wood the forests can produce. 



According to a Now Zealand journal, 

 the company has established extensive 

 works capable of treating a million feet 

 of lumber per month, and yet is quite 

 unable to cope with the rush of orders 

 received. 



In reporting on the new process, Con- 

 sul-General W, A. Prickitt says :— 



The preserving process is said to be 

 simple and inexpensive, and consists 

 essentially in boiling the wood in a 

 saccharine solution to which certain 

 other substances are added according 

 to • the special purpose for which the 

 lumber is required. The lumber is not 

 subject to any external pressure or 

 vacuum at any stage of the process. 

 The wood as it is received is immersed 

 in a cold solution in large open tanks. 

 This solution is gradually raised to 

 the boiling point and is maintained at 

 this temperature for a certain time, 

 depending on the size and density of 

 the wood. After cooling the wood is 

 removed and placed in a drying chamber, 

 the temperature of which is slowly 

 raised. When sufficient desiccation has 

 taken place the chamber is gradually 

 cooled down. The time occupied of the 

 whole treatment generally takes but 

 a few days, though in special cases and 

 for large-sized timber it may be extended 

 for several weeks. The action which 

 takes place is described as follows :— 



As the temperature of the solution in 

 which the wood is immersed is raised the 

 air in the wood expands and the greater 

 portion escapes in a series of bubbles. 

 As a saccharine solution boils at a 

 slightly higher temperature than water, 

 the moisture in the wood is converted 

 into vapour and escapes along with the 

 air. During the boiling the albuminous 

 matter in the wood is coagulated and 

 rendered inert. In some measure this 

 coagulation accounts for the strength 

 of the wood being increased by the 

 process, While cooling the solution is 

 rapidly absorbed by the wood and pene- 

 trates every part of it. 



The company is executing an order for 

 180,000 sleepers for the Government Rail- 

 way Department, and the works were 

 lately inspected by the Prime Minister. 

 The company is also treating large 

 quantities of wood for use in railway 

 cars and carriages. 



Among the advantages claimed for 

 this process is the statement that the 

 timber can be treated as soon as it is 

 brought in from the woods and then, 



