50 



THE AGKICULTURAL NEWS 



February 18, 1911. 



been the custom to attach an undue importance to the 

 effects of the climate properly termed, alone, and not 

 to give due attention to all the circumstances that are 

 included under the wider definition of the term. As 

 far as meteorological conditions are concerned, it is 

 evident that these cannot be altered by man, although 

 he can provide the animals with such shelter as will 

 assist in minimizing any evil effects from them. 



Recent research has caused a very large considera- 

 tion to be given to the minute organisms that are 

 known to produce various diseases, and to the means of 

 their transmittal, as well as to the best methods for 

 combating the diseases. In relation to the animals 

 attacked by these, other observations and investi- 

 gations have tended to show that the most deeply 

 seated changes, resulting from their introduction into 

 a new habitat, take place in the alimentary system; 

 while there is evidence, on the other hand, that there 

 is usually little alteration in the powers of reproduction. 



The period of the year at which animals should be 

 introduced into new countries depends mainly on the 

 available food-supply. Where food is plentiful, the 

 best time for this is at the cool or dry season; where, 

 however, dependence is to be had on locally produced 

 forage alone, the wet season is preferable, as then the 

 animals will meet with the new conditions, under the 

 best circumstances of nutrition. A difficulty arises, in 

 regard to newly opened lands, in that the local grasses 

 during the wet season attain a rank growth in which 

 their nutritive value is comparatively small. In the 

 article to which reference has been made, attention is 

 drawn to the interesting fact that the continued rais- 

 ing of stock in a district increases the grazing value 

 of such grasses, as the constant cropping and treading 

 down of the plants causes them to grow less i-ankly, and 

 to cover the ground much more thickly. This power of 

 grazing animals to improve the pasturage in new coun- 

 tries is a matter of the greatest importance, in relation to 

 the settlement of these. With reference .to such 

 countries, the difficulties that have been pointed out 

 already do not complete the li?t; there are others, notably 

 the likelihood of the stock being introduced into places 

 where disease is epidemic, when the lower pastures in 

 the valleys are sought during the dry season; and added 

 to this thi're is the likelihood of loss through the con- 

 sumption of unknown, poisonous plants. 



The opinion of the author is given that the ques- 

 tion of the provision of food is perhaps the most 

 important in acclimatization, more particularly as the 

 organism during this process requires a large amount.of 



energy for adaptation to the new conditions, so that 

 sufficient nourishment is a matter of necessity, if it is 

 to survive in the most useful state. As has been 

 indicated, the next matter of importance has to do with 

 the presence of the minute forms of life that cause 

 di.sease, including the ways in which these pass from 

 animal to animal. In many cases, these are not only 

 dependent for their presence on the climate, in the 

 restricted sense of the word, but the character of this 

 is often such as to make it less easy for the animals 

 to resist their attacks. The introduced animals 

 can do this chiefly through an acquired immunity, 

 and the treatment which man is enabled to accord 

 to them as a result of his study of the jjathological 

 conditions. Other useful factors in the fight against such 

 diseases are the circumstance that animals introduced 

 when young into the i-egion where they are present 

 often show an increased resistance to some of them; 

 the discovery of serums, the injection of which confers 

 immunity on the treated animals; and the ftict that 

 new means are continuall}- being found of destroy- 

 ing the intermediate hosts that harbour the |jarasites 

 of disease. 



Returning to the question of the introduction of 

 animals into tropical regions, this resolves itself into . 

 a consideration as to whether the superiority of the 

 strains shall be maintained by importation of fresh 

 animals from time to time, or whether this shall 

 be done by continual selection and careful breed- 

 ing of the material alreadv at hand. In examining 

 this matte)-, regard must be had to the fact that 

 the conditions in the new country will probably 

 be better fitted to an animal of a coarser type than 

 that which is introduced, as well as to the circumstance 

 that superior types of animals, in their struggle to sur- 

 vive in their new surroundings, will tend to degenerate, 

 as they gradually lose the jjower to transmit their 

 special characteri.stics tn their descendants. The opinion 

 is given that the best course is to commence with a type 

 that has not undergone rigid selection for particular 

 characters, and to select this in the country of its adop- 

 tion with special reference to the ([ualities that it will 

 be required to show in its new environment. The 

 ojiinion is expressed again that, in relation to all such 

 work, the question of the supply of sufficient food is of 

 primary importance in the acclimatization of the chosen 

 breeds of animals. In giving these conclusions, the 

 fact of the usefulness of the introduction of highly 

 sj^ecialized strains under fax curable conditions is not 

 forgotten, and it must be remembered that this will be 

 a matter of common feasibility in countries which have 

 been settled for a long time, and where dependence is 



