Emil Chr. Hansen 5 Særtryk 1901-1909

590 HANSEN: CONSIDERATIONS ON TECHNICAL MYCOLOGY. from 1860 and the years following, that the study of this question got out of the deadlock into which it had gradually settled down. He proved that in all cases, where spontaneous generation appeared to have taken place, some flaw or other was present in the experiments, though the method was, on the whole, correct, for instance, that impure air had not been totally excluded or that the heating had been insufficient. It was from these investigations that modern sterilisation technique was developed, which not only has become the foundation of an important branch of our laboratory work, but which now also plays an important part in practical life, as is seen, for instance, in the process now known as Pasteurisation. As long ago as 1782, the Swedish Chemist, Scheele, made practical use of Spallanzani’s experiments; he published a method for the preservation of vinegar, according to which the vinegar was put into bottles, which were then well closed and placed in a vessel containing water. The latter was then heated, and after it had boiled for some time, the bottles were taken out. Vinegar which has been treated in this manner will, as Scheele states, keep indefinitely without becoming turbid or spoilt. It is the same method which is employed to this day. A practical application of Spallanzani’s experiments, similar to that of Scheele, was made by the Frenchman, Appert, at the beginning of the nineteenth century. He employed this process to preserve wine, beer, various fruits, vegetables, soups, milk, and fruit juices. Neither Scheele nor Appert gave an explanation of what actually took place on heating. To do that was reserved for others, notably Pasteur. It is due to his experiments that this method of preservation, which had almost fallen into disuse, was again revived, and being much perfected it soon found its way into common use, in the first place for wine, and then also for beer and the other substances mentioned above. It is now used all over the world. Pasteur’s researches were of the highest value to the fermentation industries, but in 1876, after publishing his celebrated “Studies on Beer,” he left this domain to win still greater fame in that of pathology. It was at that time my fortune to take up the thread. As 1 had often observed that pitching yeast free from bacteria could nevertheless occasion diseases in the beer, and so cause great losses, this was a