Principles and discoveries of scientific nature shall not be considered to be inventions. Scientific theories and mathematical algorithms are not per se patentable because they do not show the prerequisite of a manner of manufacture. The same applies to ideas, schemes and plans. Accordingly, a biological entity may be patentable if the technical interference of man has resulted in an artificial situation which does not occur in nature. A chemical stuff or microorganism which is discovered in nature without any practical application can not be considered a subject matter patentable. Patents can not be validly obtained in respect of inventions the publication or exploitation of which would be contrary to public order and morality.