Abstract

                                There are two main spheres in which biology is of practical importance to society. One is medicine in the widest sense, which it would perhaps be more accurate to call human biology, and the other is food production or agriculture, niso in the widest sense. I do not propose to discuss the first of these fields in any detail, although new discoveries and new applications of old discoveries are always being made. Among recent new discoveries one may perhaps mention the bacteriocidal and bacteriostatic substances which are now being obtained from lower organisms. Penicillin, extracted from a mould related to the ordinary bread mould, is being investigated at Oxford and elsewhere and seems likely to prove one of the most powerful aids in dealing with infected wounds, a matter of the greatest import- ance at the present time. It may, however, be rivalled by gramicidin, a sub- stance prepared by American workers from certain types of bacteria which grow in soil; but perhaps the more optimistic view will prove justified and the two. substances be found to attack rather diferent kinds of germs and thus to supple- ment each other. As an example of a new technique of utilizing old biological knowledge, one may mention the treatment of various diseases, chiefly cancer in some of its forms, by radio-active substances artifically prepared with the aid of new physical apparatus such as the cyclotron. Radio-phosphorus and radio- iodine are differentially absorbed by different tirsues in the body; their radio- activity causes the destruction of the tissues in which they become located and the surgeon can in this way bring about a localized inhibition of particular tissues which are proliferating too rapidly.

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