Part 2 (1/2)

This has been done experimentally and proves to be feasible In practice, however, vinegara starter--by h not absolutely pure--are perfectly satisfactory It is uncertain whether really pure cultures will ever be used in this industry

LACTIC ACID

The manufacture of lactic acid is an industry of less extent than that of acetic acid, and yet it is one which has some considerable coe quantity, although it is of some value as a medicine and in the arts For its production we are wholly dependent upon bacteria It is this acid which, as we shall see, is produced in the ordinary souring of e nu the acid froar Any sample of sour milk may therefore always be depended upon to contain plenty of lactic organisms In its manufacture for commercial purposes milk is sometimes used as a source, but more coar and tartaric acid is used To start the fermentation thecheese, or both, such a anisms To be sure, it also contains many other bacteria which have different effects, but the acid producers are always so abundant and grow so vigorously that the lactic fermentation occurs in spite of all other bacteria Here also there is a possibility of an improveanisms Up to the present, however, there has been no application of such methods The commercial aspects of the industry are not upon a sufficiently large scale to call for much in this direction

At the present time the only method we have for the manufacture of lactic acid is dependent upon bacteria Chemical processes for its manufacture are known, but not employed commercially There are several different kinds of lactic acid They differ from each other in the relations of the atoms within their ht, soht, others to the left, while others are inactive in this respect All the types are produced by fer powers of producing the different types

BUTYRIC ACID

Butyric acid is another acid for which we are chiefly dependent upon bacteria This acid is of no very great importance, and its manufacture can hardly be called an industry; still it is to a certain extent made, and is an article of commerce It is an acid that can be manufactured by chemical means, but, as in the case of the last two acids, its commercial manufacture is based upon bacterial action Quite a number of species of bacteria can produce butyric acid, and they produce it froredient in old milk and in butter, and its formation by bacteria was historically one of the first bacterial fermentations to be clearly understood It can be produced also in various sugar and starchy solutions

Glycerine o a butyric fermentation The presence of this acid is occasionally troublesome, since it is one of the factors in the rancidity of butter and other similar materials

INDIGO PREPARATION

The preparation of indigo froht about by a specific bacteriue vat, and a rapid fermentation arises As a result of the fermentation the part of the plant which is the basis of the indigo is separated from the leaves and dissolved in the water; and as a second feature of the fered in its chee occurs the characteristic blue colour is developed, and the material is rendered insoluble in water It therefore makes its appearance as a blue o

Of the nature of the process we as yet know very little That it is a fermentation is certain, and it has been proved that it is produced by a definite species of bacteriuo leaves If the sterilized leaves are placed in sterile water no fero is formed If, however, some of the specific bacteria are added to the ins and the blue colour of the indigo o is a product of bacterial ferle definite species of bacterium Of the details of the formation, however, we as yet know little, and no practical application of the facts have yet been made

BACTERIA IN TOBACCO CURING

A fermentative process of quite a different nature, but of immense commercial value, is found in the preparation of tobacco The process by which tobacco is prepared is a long and so of a nu first dried in a careful manner, is subsequently allowed to absorb e heaps to undergo a further change This process appears to be a fermentation, for the temperature of the mass rises rapidly, and every indication of a fered occasionally, the heap being thron and built up again in such a way that the portion which was first at the bottom comes to the top, and in this way all parts of the heap may become equally affected by the process After this process the tobacco is sent to the differentThe further treat to the desired product, whether for s or for snuff, etc In all cases, however, fermentations play a prominent part So material In the preparation of snuff the details of the process aretobacco The tobacco, after being ground and o a fermentation which lasts for weeks, and indeed forsnuff the fermentations take place in different ways, and sometimes the tobacco is subjected to two or three different fermentative actions The result of the whole is the slow preparation of the co the final fermentative processes that the peculiar colour and flavour of the snuff are developed, and it is during the fer tobacco--either the original fermentation or the subsequent ones-- that the special flavours and aromas of tobacco are produced

It can not be claies by which the tobacco is cured and finally brought to a marketable condition are due wholly to bacteria There is no question that chemical and physical phenomena play an important part in them Nevertheless, from the moment when the tobacco is cut in the fields until the ti is very intianisht about by bacterial life; in others the h they perhaps can not be regarded as the sole agents

At the outset the tobacco producer has to contend with a nuanis the drying process, if the temperature or the amount of moisture or the access of air is not kept in a proper condition, various troubles arise and various diseases make their appearance, which either injure or ruin the value of the product These appear to be produced bythe fer the producer has to contend with anisms that are troublesoulated the fermentation that occurs produces effects upon the tobacco which ruin its character Froe in the curing the persons engaged in preparing it for roithin it of undesirable organisms The preparation of tobacco is for this reason a delicate operation, and one that will be very likely to fail unless the greatest care is taken In the several fermentative processes which occur in the preparation there is no question that anisms aid the tobacco producer and manufacturer

Bacteria produce the first feranisive rise to all the subsequent ferly in some cases purely chemical processes materially aid Now the special quality of the tobacco is in part dependent upon the peculiar type of fer actions It is the ferives rise to the peculiar flavour and to the arorades of tobacco

Inasmuch as the various flavours which characterize tobacco of different grades are developed, at least to a large extent, during the fermentation processes, it is a natural supposition that the different qualities of the tobacco, so far as concerns flavour, are due to the different types of fermentation The number of species of bacteria which are found upon the tobacco leaves in the various stages of its preparation is quite large, and from e have already learned it is inevitable that the different kinds of bacteria will produce different results in the fer process

It would seem natural, therefore, to assurades may not unlikely be due to the fact that the tobacco in the different cases has been fermented under the influence of different kinds of bacteria

Nor is this simply a matter of inference To a certain extent experiiven at least a slight indication of practical results in the future

Acting upon the suggestion that the difference between the high grades of tobacco and the poorer grades is due to the character of the bacteria that produce the ferists have atteh quality of tobacco the species of bacteria which are infesting it These bacteria have then been cultivated by bacteriological methods and used in experiments for the ferrade tobacco is in large measure, or even in part, due to the action of the peculiar ht to be possible to produce sirown in other localities, if the fermentation of the leaves is carried on by h grade tobacco Not very much has been done or is known in this connection as yet Two bacteriologists have experi tobacco leaves by the action of pure cultures of bacteria obtained from such sources Each of them reports successful experiments

Each claims that they have been able to i the leaves with a pure culture of bacteria obtained froh quality in flavour In addition to this, several other bacteriologists have carried on experiments sufficient to indicate that the flavours of the tobacco and the character of the ripening ed by the use of different species ofthe curing processes

In regard to the whole nise that as yet we have very little knowledge The subject has been under investigation for only a short time; and, while considerable inforhly understood, and our knowledge in regard to the matter is as yet in rather a chaotic condition It seee measure dependent upon the character of the fer It seems certain also that these feranise anisms that produce it If these are facts, it would seem not improbable that a further study reat industry The study of yeasts and theyeast fro industry Perhaps in this other ferreat commercial extent, the use of pure cultures of bacteria reat revolutions in methods as it has in the industry of the alcoholic fermentation

It rades of tobacco grown in different parts of the world are due solely to variations in the curing processes and to the types of fermentation There are differences in the texture of the leaves, differences in the chemical composition of the tobaccoes, which are due undoubtedly to the soils and the clirow, and these, of course, will never be affected by changing the character of the ferment active processes It is, however, probable that in so far as the flavours that distinguish the high and low grades of tobacco are due to the character of the fermentative processes, they e extent, controlled by the use of pure cultures in curing processes Seereat a future in the development of this fermentative industry as there has been in the past in the develop and vinting

OPIUM

Opiu process which lasts severalof tobacco Apparently it is a feranisms in question are not, however, bacteria in this case, but a species of allied fungus The plant is a mould, and it is claimed that inoculation of the opiu

TROUBLESOME FERMENTATIONS

Before leaving this branch of the subject it is necessary to notice so with our industries, requiring specialspecial industries to ents of decomposition, bacteria will of course be a trouble whenever they get into material which it is desired to preserve