Louis Pasteur: His Life and Labours

tant it required nothing less than his engagement with Mademoiselle Marie Laurent, daughter of the Rector of the Academy. It is even asserted th

e proved as a husband so different from La Fontaine that Madame Pasteur, when r

ich deposit themselves in liquids under well-determined crystalline forms. Without entering into the details of these long and patient studies, it may be stated generally that Pasteur proved that whatever could be done with one of the tartaric acids could be repeated rigorously, under similar conditions, with the other, the resultant products manifesting constantly the same properties, with the single difference already

rches. M. Biot was again the reporter. It was with a sort of coquetry that Pasteur brought from Strasburg perfectly labelled specimens of the magnificent crystall

he spent several hours in conversation with Pasteur. M. Biot became so excited during the discussion that Madame Bio

moires of the Academy. This was an exceptional honour. Arrived for the most part at the end of their own careers, these

scherlich somewhere about that time, 'you may boast of having done som

much care and perseverance, in their smallest details, the two salts which formed the subject of my note to the Academy, t

dissymmetry in the internal molecular arrangement of a chemical substance ought to man

ed light, as liquids or solutions, were generally found by Pasteur to produce dissymmetric crystals. Some of them, however, notwithstanding their power of crystallisation, exhibited, when crystallised, no dissymmetric face. This difficulty did not deter Pasteur. It gave him, on the contrary, the opportunity of showing that when a theory had in so many cases

uced into the solution, sometimes an excess of acid or of base, sometimes foreign matters incapable of acting chemically upon those which were to be modified; he even employed sometimes impure mother liquids. On each occasion new facets were thus produced, and these new facets showed the kind of dissymmetry which the optical character demanded. Although he

say all the products of inorganic nature-have a superposable image, and are therefore not dissymmetrical, while vegetable and animal products-in other words, products formed under the influence of life-have an image not superposable; that is to say, they are atomically dissymmetrical, this dissymmetry expressing itself externally in the power of

e the result of secondary actions. Their formation is evidently governed by the laws which determine the constitution of the artificial products of our laboratories, or of the mineral kingdom properly so called. In living beings they are the products of excretion rather than substances essential to vegetable or animal life. When, on the other hand, we consider the most primordial substances of vegetables and

issymmetry. It may also be affirmed that the substances which exert the greatest influence in vital manifestations, which are present an

atory, the number of which is each day augmented, should manifest either the power of turning the plane of polarisation or non-superposable dissymmetry? No doubt natural dissymmetric substances-gum, sugar, tartaric and malic acids, quinine, strychnine, essence of turpentine, &c.-may be employed in forming new compounds which re

symmetrical order; while the forces which are present and active at the moment when the grain sprouts, when the egg develops, and when, under the influence of the sun, the green matter of the leaves decomposes the carbonic acid of the air and utilises in divers ways the carbon of this acid, t

of bodies which compose the solar system, with their proper movements, we obtain in the mirror an image not superposable on the reality. Even the motion of solar light is dissymmetrical. A luminous ray never strikes in a straight line, and at rest, the leaf wherein or

ollow them to the issues of which he dreamed; but to this day he remains persuaded that the barrier which exists between the mineral and organic kingdoms-and which is revealed to our eyes by the impossibility of producing, in the reactions of the laboratory, dissymmetric organic substances-can never be crossed until we have succeeded in introducing among these reactions influences of the dissymmetric order. According to Pasteur, success in this direction would give access to a new world of substances, and probably also of organic transformations. As we have succeeded in finding the inverse of right-handed tartaric acid, we may hope to obtain some day all the immediate principles inverse to those now known to us. Who could say what vegetable and animal species would become if it were possible to replace, in the living cells, cellulose, albumen, and their congeners, by their isomers with an inverse action? Certainly the thing is not easy, and Pasteur would be the last person to deceive himself as to the difficulty of the problem. His latest thought on the matter is this:-When the attempt is made to introduce into living species primordial substances, inv

the state of solution they did not turn the plane of polarised light. Aspartic acid, on the contrary, had presented to him molecular dissymmetry, like asparagine itself. If the observation of M. Dessaignes were true, then bodies which were inert in regard to polarised light, and consequently non-dissymmetric, could be transformed in the laboratory into active dissymmetric bodies. The line of demarcation so well established would be broken. Pasteur, whose experience regarding the note of Mitscherlich had shown him how even the most conscientious observers may fail to seize upon fugitive appearance

id from succinic acid, artificial and inert, by Perkin and Duppa-Pasteur testified with absolute certainty of judgment to the existence of phenomenal peculi

rystallographic physics and the new and entirely unexpected results of physiological chemistry. This connection, like the thread of Ariadne, conducted hi

hat we are enabled to appreciate the rigour of judgment of that learned man in forming his conclusions, and the perspicacity