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   THE LEARNED-MAN, HIS WORKS, HIS DISCOVERIES

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After having thus spoken about the man, of his life and its character, we interest in the scientist and his?uvre. During 25 years, the scientific activity of Mr. Maillard is truly extraordinary. Some a hundred and fifty publications all, of the most scientific interest, mark out its course. All its work carries the mark of a deeply original spirit and a technician particularly informed. Mr. Maillard had to it solid culture which confers the science doctorate physics. He was a truly complete chemist, as educated in organic chemistry as in inorganic or analytical chemistry, but at his place the chemist doubled of a biologist of a rare perspicacity. One can say of him that he was a biochemist, in all the force of the term.

 Mr. Maillard did not forget either that he was a doctor and it is with medical biochemistry that he devoted the greatest part of his activity. Its vast knowledge, joined to a beautiful intelligence and a not very common energy, enabled him to conceive and conclude a great number of work, whose principal ones will remain traditional in annals of Science. Work of Mr. Maillard is referred on six principal subjects which are: 

 It is in its thesis of doctorate in medicine, in 1903, that Mr. Maillard gathered the results of research which it had already continued for several years on urinary indoxyle and them dyes of the group of the indigo. One cannot read this work without noting the direction of the experimentation and the particular skill of his author. Its remarks are at the base of several techniques of research and proportioning of the urinary indoxyle which it developed with a care meticulous person. He studied, moreover, the blue dyes or red soluble in chloroform which exist sometimes preformed in the urine. This study (phenomena of Maillard) enabled him to make disappear from the nomenclature of many dyes unduly described like distinct individualities and which did not have any right to the existence.

 After having made?uvre of chemist, Mr. Maillard did not fail to study as a doctor the question of urinary indoxyle. He even returned several times there during his career, in particular in connection with the important quantitative study which he made of the normal urine. Mr. Maillard showed that the indoxyle must be classified among its constant components, but irregular. While devoting itself to this important quantitative study on the urine, Mr. MAILLARD also studies the need for food of these soldiers. Analyzing with precise details the meals of the soldiers, it writes a remarkable report/ratio on the real nutritional needs for the quota. Transmitted to the Ministry for the War, this report/ratio will involve the modification of the military rations since 1908.

 It is being studied of the metabolism of nitrogen that it contributed the most important share. In this study on the normal urine, published in 1909, Mr. Maillard made known the coefficient which bears its name. Mr. Maillard allotted to his coefficient the significance of an index of ureogenic imperfection. However, Mr. Maillard itself as of his first publication on this subject pointed out the possible influence of the organic acids having been able to escape from total degradation. The neutralizing role of ammonia was indeed already well-known at that time. One knows today the important function of the kidney in the maintenance of balance acid-bases. It secretes a quantity of ammonia in connection with the quantity of acid introduced into the organization or generated by the normal or pathological metabolism.

 That they are the shapes of elimination of nitrogen, the mechanism of the assimilation of the nitrogenized substances, or even of the cycle of nitrogen in nature, one can say that it is with the biological role of this metalloid that Mr. Maillard devoted the best of his activity.

 However, making way, it did not neglect to be interested on other important subjects. Thus having the attention drawn by colloidal sulphur, it decides into 1911 to tackle the complex problems posed by the metabolism of sulphur, by taking as starting point this element with the state of colloidal solution.

 This physical state, characterized by an extreme division, seems to him to have to support the absorption and the metabolism of sulphur. First aid of Mr. Maillard is to seek a method of preparation of colloidal sulphur giving a product always identical to itself and very stable. In 1911, these conditions are met by no known method.

 Mr. Maillard succeeds in developing the method of Wackenroder which gives him perfectly stable preparations of colloidal sulphur. Introduced by animals of laboratory, this colloidal sulphur was absorbed in the proportion of 90 % as the analysis of the faeces and the urine showed it.

 The determination of the various shapes of urinary sulphur gave the following results: about half of colloidal sulphur is eliminated in the form of sulphates; there is in addition a clear increase in sulfo-combined, and finally an important proportion of colloidal sulphur is eliminated in a form belonging so that he is agreed to call neutral sulphur or incompletely oxidized. Bringing abundance closer to composed of neutral sulphur of the increase of sulfo-combined, Mr. Maillard put forth the following assumption:

 For him, the conjugation would be done with compounds of reduced sulphur, standard cysteine, and oxidation would take place only after the conjugation. Work of the Sherwin American seems to bring a confirmation to this manner of including/understanding the important mechanism by which the elimination of various organic poisons is done.

 Although driving of face his research of physiological chemistry and work of pure organic chemistry on the amino acids, Mr. Maillard did not lose sight of the fact the possible applications to therapeutic of his method of preparation of colloidal sulphur. He published with professor Albert Robin a study on the treatment of chronic rheumatism and the respiratory affections by colloidal sulphur. He moreover inspired one thesis on this subject.

 By his masterly studies on urinary chemistry, on the metabolism of nitrogen and sulphur, Mr. Maillard had already given his measurement like biochemist. Its vast knowledge, its consumed experimental skill, enabled him to tackle a question of particularly delicate organic chemistry, the syntheses of peptides. Its direct idea was, said it, the research of the mechanism of formation of the proteins in the animal organization by welding of the amino acids. I do not believe to mislead to me by saying that its secret thought was the hope to discover the true structure of proteins.

 The methods used by Emil Fischer for the synthesis of peptides, based on the use of acid chlorides are, obviously, absolutely foreign with those which nature employs. Mr. Maillard had the idea to seek the amino possibility of linking two or several acids by softer methods and can be comparable with what occurs in the organization. He fully succeeded in this company by discovering that the amino acids can combine between them by simple heating within glycerin (or of glycerol, like one says today).

 He obtained thus, by a new method, an important series of cyclic compounds already known in which the amino acids put in presence are reciprocally plain by their two functional groupings. They are cyclopeptides, to employ the term which it itself forged. The cyclopeptides can result from the union of two similar amino acids or two different amino acids

 If it is considered that in all these preparations beside a principal product various secondary compounds are formed, one easily realizes of the considerable work which required separation, the purification and the identification of all these substances. This work was made according to the most strict rules' of the organic chemistry. It was worth with its author the rank highly deserved of science doctor physics, in June 1913. 

The interest which sticks to the cyclopeptides comes from the impressive arguments which one can put forward in favour of the existence of their cycle in the molecule of proteins. In the second part of his thesis, Mr. Maillard studied the action of sugars on the amino acids. This reaction, remarkably easy, leads to the formation of brown products of appearance similar to the natural humus. The comparative study of these products and those which it withdrew from the topsoil showed that they were substances at least very close.

 One can thus say that Mr. Maillard made a success of at the laboratory the artificial propagation of an important natural phenomenon, and in the mechanism elucidated. Indeed, in nature, of the glucides hydrolysables out of sugars are constantly in contact with proteins hydrolysables in amino acids. One could not too much stress the importance of this discovery, however little known of the medical world.

 After its thesis of sciences and various publications being attached to it, the interruption of its personal research is placed, imposed by the war. Exempted active service in times of peace because of his sight, Mr. Maillard engages for the duration of the war as of July 30, 1914.

 Named to the biological Pulpit of chemistry of the Faculty of Algiers in 1919, Mr. Maillard devoted his activity to his teaching, to which it could print a deeply original character. He had the concern, pushed until the scruple, to hold it with the current of the most recent work, while eliminating in a pitiless way what did not appear to him not established with enough certainty.

 During the years which follow the war, a lassitude easily explicable by the extraordinary activity which it had deployed, immediately does not enable him to continue its scientific research. Ten years later, it resumes experimental work or at least the direction of research. It found in Algiers a collaborator worthy of him.

 It is infinitely small chemical, the titanium, which holds its attention. With Mr. Ettori, it develops a method of proportioning of the titanium which is characterized by a particularly elegant design and an extreme sensitivity (X by 300). It indeed makes it possible to proportion this element on test specimens which contain only few thousandth milligram of it. This method is applied to proportioning of titanium in blood and the bodies of the man and various animals. It makes it possible to show for the 1era time that titanium exists in a constant way, although with very weak amount, in the blood and all the bodies of the man and the principal mammals. The last communication of Mr. Maillard on this subject appears after its death.                       

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 Let us add to this essential work the true bible which the Treaty of Histology represents and still announce the communications of Louis Camille made on Nancy. Although?uvres of youth, they show the eclecticism and the serious one of the scientist.

- the influence of limestone on the vegetation,

- loaches of pond,

- the presence of vanillin in the Lorraine orchises,

- On a crystallized fibrin of blood

- pectoral small Muscle and rachidian tandem,

- Copper sulfate on frogs,

- Copper sulfate and Penicillium glaucum,

- Ionization in the vital phenomena, etc, as many articles which make known Mr. Maillard beyond Lorraine. Louis Camille MAILLARD is at the origin of the creation of many new terms corresponding to his discoveries and introduced with the Richet dictionary since 1910 (the indol and cyclopeptides for example).

 Mr. Maillard left a scientific?uvre considerable and highly appreciated in France and abroad. By traversing it, one remains truly astonished by the number and the quality of work which it published in a so short time. The summary that I have just made can give only one quite incomplete idea of it.

 At the scientific level, the history preserved the name of MAILLARD by associating it several names and formulas:

 Hémi indigotin of Maillard

Phenomena of Maillard (indigotin and indirubin)

Coefficient of Maillard (index of ureogenic imperfection)

And of course immortal "reaction of Maillard" (action of sugars on the amino acids) which will be worth with its author a universal posthumous radiation.

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