culture may note with satisfaction that the potato-drying industry has been the model which yeast drying has followed. Of the existing yeastdrying systems the greater number of apparatus are built by those firms which have already made a name by their potato driers for producing potato flakes. Also the build of yeast driers is in the main based on the experience gained in the construction of potato driers. The principle upon which all these apparatus are designed is essentially the same. The moist yeast passes over steam-heated cylinders, dries in fractions of a minute on them and is continuously scraped off the revolving cylinders by stationary blades. The section of alimentary physiology of the Institute of Fermentation Industries in Berlin, to which the Institute of Experiment and Instruction. in Brewing is attached, has also supplied the scientific and practical foundations for the practice of feeding dry yeast. Formerly very little was known on this subjert. Now, thanks to the researches of Völtz and his collaborators Paechtner and Baudrexel, carried out in the above section, it is known that dry yeast is one of the richest concentrated foods, that it is relished and well assimilated by all kinds of live stock, and that it is especially suitable for fattening purposes. The writer was the first to draw attention to the fact that dry yeast is not one of those foods the price of which corresponds to its calcutated food value (like potatoes, maize, barley) but belongs to those whose price, owing to special dietetic properties, lies considerably higher than their calculated food value would warrant (oats, fish-meal, flesh-meal). The above researches furnished the following data: Sheep (1) utilize 94 per cent. of the organic matter, 88 per cent. of the crude protein aud upwards of 100 per cent. of the nitrogen-free extract (2) of the dried yeast, which has a higher nutritive value than cottonseed meal. For horses (3) more than half of their grain ration may be replaced by a corresponding quantity of nutritive substance in the form of dried yeast and dried potatoes without prejudice to their health, appearance or performance. For pigs (4) a mixture of dried potatoes, dried yeast and some barley, without any dairy by-products, forms a suitable rapidly fattering ration for young animals. For poultry (5) as regards laying, and for the fattening of geese (6) (1) VÖLTZ: Jahrbuch der Versuchs- und Lehranstalt für Brauerel in Berlin, 1910, p. 403; and Zeitschrift für Spiritusindustrie, 1910, Nos. 48 and 49. (2) This high utilization figure is due to a better utilization of the basal ration caused by the addition of yeast. (3) VÖLTZ: Zeitschrift für Spiritusindustrie, 1910, No. 47. (4) VÖLTZ: Wochenschrift für Brauerei, 1911, Nos. 45 and 46; Zeitschrift für SpiritusIndustrie, 1912, Nos. 1-4; Landwirtschaftliche Jahrbücher, 1912. (5) VÖLTZ (Work not yet published). (6) VÖLTZ: Wochenschrift für Braueret, 1913, No. 11. and the quality of their flesh, dried yeast proved equal to meat meal (calculating equal amounts of nutritive units). With milch-cows (1) the use of dried yeast increases the butter-fat content of the milk. In numerous cases it could be demonstrated that feeding the mixture of dried potatoes and dried yeast which has been recognized as very suitable, allows of considerable economy in the cost of keeping live stock. (The essential results of these researches are collected in the papers of Völtz, Paechtner and Baudrexel «On the utilization of dried yeast by live stock »: Landwirtschaftliche Jahrbücher, 1912). The excellent results which have attended the practical use of dried yeast have caused such a demand for the new food, especially of late, that the supply has fallen decidelly short, notwithstanding the fact that between 1910 and 1913 the number of yeast-drying works has risen from 5 to 26 (of which II are in Germany). Correspondingly to the increased demand, the price has risen in the same period from 8s or 9s to 10s 6d or IIS 6d per cwt. But the highest limit is not yet reached, because the present price does not correspond to the real value of dried yeast, which consists to a great extent in the increased appetite that this food gives. The German brewing industry alone is capable of turning out every year about 20 000 tons of this valuable food. For farmers it will be interesting to learn that they have, often not knowing it, practised feeding yeast for a number of years, when they have used distillers' refuse. This refuse contains all the yeast which forms during the fermentation of the mash. In this connection the following calculation may be made: 100 parts in weight of distillery refuse contain 4 parts of yeast (calculated as compressed yeast). II gallons of this refuse per head of cattle daily contains 4.4 lbs. of yeast. For every 100 gallons of pure alcohol, 400 lbs. of yeast are formed, and as in the German potato distilleries about 61 000 000 gallons of pure alcohol are produced per year the farms that distil potatoes feed to their stock about 117 500 tons of yeast, equal to 35 425 tons of dry yeast. The yeast content of distillers' refuse is not its least valuable part. For those farms which have no such refuse or possess it in insufficient quantity, brewers' dried yeast is a valuable substitute. The yeast intended for stock feeding is not freed from its bitter principle before drying, but is worked up as it comes from the fermentation vat. The Institute for Experiments and Instructier ir Brewir g ir. Berlin has, however undertaken to free the yeast carefully from the hcp resin that it contains, in order to prepare it as humar. fccd. The work dcre in this direction has led to surprisir g results. By mears of a competitier it has been shown that this purified dried yeast (Fccd yeast) car be used (1) VÖLTZ (Work not yet published). in the preparation of a number of savoury dishes and renders good service in domestic economy. Experiments made on a number of persons have proved that this food yeast is wholesome and easily digested, and that to a great extent it can replace meat in human food. In the course of these investigations it was ascertained (1) that I lb. of this food yeast was equal in food value to 3.3 lbs. of average fat beef. But it is not only an article of food, but, as it has been demonstrated by a number of medical experiments, it is also a means of invigorating weakened organisms. Its power of giving an appetite to debilitated subjects who suffer from inappetence is especially to be mentioned. This specific action of food yeast is perhaps due to its not indifferent lecithin content (N over 2 per cent.). The preparation of food yeast has been for the last eighteen months carried on regularly in a properly equipped purifying and drying installation, and the prepared yeast is daily gaining ground as an invigorating article of food. There is the prospect that this branch also of yeast drying will soon develop to an independent industry. The chief consumption of this food yeast will not be so much in private households as in the food industry, where there is a great demand for savoury material rich in protein. At the present price of 2s 2 3/4 d per lb., and considering equal quantities of nutritive elements, food yeast is cheaper than meat. And in the wholesale transactions with the food factories the prices might be considerably reduced. According to the present state of the technique, all the excess yeast of German breweries could yield a yearly output of 13 750 tors of food yeast, equivalent to about 45 200 tons of medium fat beef. The raw material is sufficient to give rise to an important industry. How much of the excess of brewers' yeast will eventually be put to this use can not be foreseen. For the moment the bulk of dried yeast will be used for the preparation of yeast for live stock, and the production of food yeast will form only a branch of this industry. It must also be remembered that the use of yeast as food is to a certain extent no novelty, for yeast has always been consumed in the shape of baker's goods, and in considerable quantities too, amour ting in Germany alone to 147 000 tons (calculated as compressed yeast) per year, as the 49 000 tons of yeast required by the bakers becomes three times as much in the dough. (1) VÖLTZ and BAUDREXEL: Blochemische Zeitschrift, 1911, Vol. 30, Part 6; and Vol. 31, Parts 3 and 4. The Control of the Japanese Fruit Scale by Prof. ANTONIO BERLESE, Director of the Royal Station of Agricultural Entomology at Florence. The experience of many years has shown that the artificial control measures used against Diaspis pentagona are of value only for the season in which they are carried out, and cannot be expected to get rid of the scales permanently or sufficiently to allow of the healthy growth of the plants. This is the reason of the general complaints about these measures and the doubts entertained by mulberry-growers as to the value of the control, doubts which are all the more in evidence where the disillusion is older, that is where the scales have been present longest. The natural methods are thus aimed, not at the extermination of the Diaspis from its present quarters, as this would be impossible, but at securing an activity sufficient to take the place of the artificial means, even if these were repeatedly and energetically employed, or in other words to prevent the Diaspis doing any damage. Among natural means predatory insects are now no longer considered: indeed it was already foreseen two years ago, when they were first talked about, that they would not be sufficient. The only remaining enemy of any value is Prospaltella berlesei, a small species of the Hymer.optera which is the special endophagous parasite of Diaspis pentagona. I have already, in two earlier papers (1), described its introduction into Italy and its diffusion in the peninsula during the first three years, 1908 to 1911. We may now discuss the present state of affairs in the control of Diaspis. For this purpose it may be well to consider first what is going on in neighbouring countries, namely in Switzerland and over the border of the Empire of Austria-Hungary, where Diaspis is present to a serious extent. In Switzerland it was only last year that Prospaltella was imported and let loose, and I have just found that it has established itself in the neighbourhood of Locarno. In the Trentino (Austria), Prof. Osvaldo Orsi, of the Royal-Imperial Agricultural Institute of San Michele, begar importing the insect in 1909; it has since been carefully distributed in the territories of Ala, Riva, Rovereto and Trent, altogether in 12 jurisdictions, comprising 37 communes; it was let loose at 28 centres on 1478 mulberries, and from these (1) A. BERLESE: La Diaspis penta zona e gli insetti suoi nemici. - L'Italia agricola, 1911; also Redia, Vol. VI, Part 2, p. 298, 1911. ID.: Come progredisce la Prospaltella berlesei in Italia. Redia, Vol. VII, Part 2, p. 436. (Author's note). it is spreading out naturally or with assistance to all the surrounding The excellent results attained are attested by a pamphlet published by the Provincial Agricultural Council of Trent (bibl. 1), and by several articles in different newspapers, among which I may note one by Prof. Orsi entitled: "La Diaspis del Gelso è vinta" (The Mulberry Diaspis is defeated), published in the organ of the Trent Farmers' Association (bibl. 13). In Göritz the spreading of Prospaltella was carried out very carefully by Prof. Bolle, who obtained living examples even from Japan. The parasite is now well distributed in many centres and its good effects have recently been described by Prof. Bolle in a study entitled "Die Maulbeerbaumschildlaus (Diaspis pentagona) und die Mittel zu ihrer Bekämpfung" (bibl. 8). The Director of the Royal-Imperial Station of Agricultural Chemistry of Göritz, after giving the results of his experiments made in 1910, 1911 and 1912, comes to the conclusions that I had already reached, in particular that Prospaltella is an efficient means of controlling Diaspis, completely replacing the most efficacious artificial means carefully applied every year. In Istria Prospaltella is now widely spread, according to Prof. Bolle, and the Royal Station at Florence possesses documents showing that it was introduced there in 1909. The Austrian Government has twice sent competent persons to visit the centres of infection of Prospaltella and study its effect; as a result, the Government arranged an extensive distribution of the insect in the Trentino, Göritz, Istria and Dalmatia, as well as to silkworm observatories in Italian territory, and printed instructions, illustrated leaflets, etc., were prepared. In our peninsula the oldest introductions of Prospaltella are at Vanzago, near Milan; Acerra, near Naples; the Palombina, near Ancona; Grottammare in the Marches; and Genoa. Vanzago supplied the bulk of the material for distribution, so that Prospaltella has become uncommon there; but all the same Diaspis is now very scarce, as the parasite spread naturally from the few infested scales which were left here and there in spite of the most careful search for material. In the country round the scale is abundant, but the parasite has not been assisted to spread. The effect of Prospaltella at Vanzago is referred to again in the Bollettino dell'Agricoltura, organ of the Lombardy Agricultural Society, for April 11, 1913; to this Dr. Del Bo, travelling lecturer in agriculture at Milan, contributes an article entitled "L'esperienza di Vanzago conferma la bontà della Prospaltella." (The results at Vanzago confirm the usefulness of Prospaltella). He says that a party of representatives from the Lombardy Agricultural Society, from the Association of Silkworm Egg Breeders, and from the travelling lectureship, were able to recognize that the Prospaltella "represents a providential assistance of enormous value against Diaspis" and "makes all other methods of control unnecessary." He concludes that farmers should have "unlimited confidence in the new means of control." At Acerra, Sig. Nuzzo's mulberry |