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NEW BOOKS Die Kolloide in Bioloeie und Medizin. By If. Urchhulii. Fij’th, c u ~ i p l r t e l yrci’iserl d i t i o i z . 23 X 16 crri. pi). x i i i ,586. Dresdeii and L e i p i g : l h e o d o r Steinkorff, 1.929. P r i c e : 33 ?narks; hourid 3.5 marks. This is the fifth edition in name and the third edition in fact, because the so-called third and fourth editions Tvere merely the second edition reprinted. The great change in the last ten years is that biology and medicine have begun to recognize the importance to each of colloid chemistry. Colloid-chemical and colloid-physical investigations now dominate the experimental research work on physiological and pathological processes. The book is divided into four parts. The first part gives an introduction to colloid chemistry, with chapters entitled: what are colloids?; surfaces; particles, micelles, molecules, ions, dynads, individual groups; motion phenomena; optical and electrical properties of colloids; methods of research in colloids. The general subject of the second part is biocolloids and the individual chapters deal with: carbohydrates; lipoids; proteins; food and drink; enzymes; immunity reactions. The third part is concerned with the organism as a colloid system and the eight chapters have as headings; distribution and conversion of substances; form developmmt and change, growth and development; cell and tissue; movements of organisms; blood, breathing, circulatory flow and its disturbances; resportion; secretions and excretions; nerves. The fourth part is devoted to toxicology, pharmacology. and therapy, and to microscopical technique. “Chemical reasons indicate that albumin has a very high molecular weight. Even if we assumed that it was completely dissociated into single molecules in aqueous solution, these would still be so large that they could not pass through animal and vegetable membranes. The undamaged membranes of the organism therefore protect completely against loss of albumin. I t is only in pathological states, such as disease of the kidneys, that albumin passes through,” p. 2 . Seuberg found that organic acids, such as benzoic and naphthenic acids, carried water-insoluble substances such as calcium carbonate, magnesium phosphate, insoluble soaps, dyes, fats, starch, hydrocarbons, etc., into apparent solution in water. He termed the phenomenon hydrotropy. There is no explanation as yet for this, p. j. Bechhold agrees with Mecklenberg that the differences in the stannic acids are structural differences and not chemical ones, p. 8. He quotes approvingly the conclusion by Martin Fischer that the green, yellow, orange and red colors of cuprous oxide are due to the sizes of the particles, the red ones being the coarsest. On the other hand he does not seem to know that Anderson’s calculations of the pore sizes of gelatine are inaccurate, p. I I , Lecithin is an effective protecting colloid in chloroform, p. 1 2 . When the oil drops of an emulsion are 0 . 4 in ~ diameter, it takes 20 Atm. to force them through pores of 7 5 n i in~ diameter. In one case an oil emulsion came through a collodion membrane clear under a pressure of 6 Atm. and cloudy under a pressure of I O Atm., p. I;. Charcoal which has been shaken with the solution of a coal-tar dye often shows the green luster of the solid dye, p. 27. Unfortunately, Bechhold believes that the. adsorbed dye is changed chemically, p. 28. Starch and coagulated albumin adsorb alkaloids strongly, p. 30. Bechhold attributes t o himself and not to Pickering the fact that one can form emulsions with solid powders as emulsifying agents, p. 38. Clowes never said that emulsions were especially instable when the two liquids are present in equal volumes, p. 39. On p. 44 the author commits the common error of speaking of colloid molecules when he means colloid particles. “We distinguish very often bet ween molecular weight and molecular aggregate weight (or molar weight). For gelatine for instance, they have deduced a molecular weight of 8jo-1100from the power to bind hydrochloric acid [which only gives a molecular weight in

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case one assumes that gelatine is a monacid base], while the molecular aggregate weight is about 30000 from measurements of osmotic pressure and from similar methods. This means that about thirty single molecules are held together, perhaps by ‘secondary’ valences, in a larger complex (micelle). In general we can say that colloids are almost always dissolved as micelles,” p. 47. This use of the word micelle is not at all that adopted by McBain. Since people object to speaking of molecules in a sodium chloride crystal the author suggests calling the solid matter a dynad, p. 47. Perrin’s calculations on gamboge solutions are apparently assumed to be accurate, p. 52. Urea increases the rate of swelling of gelatine, p. 56. The antagonistic action of salts is ascribed to the effect of the cations on the swelling of gelatinous colloids, p. 75. “All our experience‘indicates that the swelling and shrinking of hydrophilic gels runs parallel with the formation of ions and of neutral particles by albumin,” p. 76. “Quincke observed, in the artificial clearing of mastic, gamboge, kaolin, and ink suspension, that the flocks usually deposited on the shady side; with spontaneous clearing of kaolin suspensions on the illuminated side. With tannin and glue the precipitate forms mostlyon the illuminated side. Quincke called this positive and negative photodromy,” p. 85. “L. Karszag has made a very important discovery which has been followed up by his students. He took a dye solution, Fuchsin S for instance, shook it with kaolin, let it stand for several hours, and then filtered. The filtrate was colorless. On adding hydrochloric acid to the filtrate, the solution became colored again. The dye had therefore been changed chemically by the kaolin. Kaolin has therefore the property of converting the dye into the colorless carbinol,” p. 101. If this account is correct and if the dye was in the solution in the carbinol form, that can only mean that the kaolin adsorbed the hydrochloric acid and left the dye in solution. While that is interesting, it is not particularly thrilling. What would have been really interesting would have been for the kaolin to have adsorbed the fuchsin in the carbinol form. “The best known reagent for starch is iodine, which colors it blue in the cold; the color disappears on heating. It used to be assumed that iodine formed a chemical compound with starch. The more recent investigations have proved conclusively that the blue iodine-starch is an adsorption complex, in which the iodine has diffused into the starch micelle to an amount which varies with the length of action. “There are many other substances which give the iodine reaction, for instance lanthanum acetate [basic], saponarin (a glucoside), narcein, etc. Most convincing for the characterization of the iodine reaction are the phenomena with cholic acid. So long as this is in true solution, there is no color change. The blue iodine-cholic acid forms only when the cholic acid crystallizes or is precipitated as an amorphous mass, in other words when the molecules come together to form aggregates or micelles. . . Other forms of starch are colored yellow by iodine, inulin, for instance, while glycogen becomes yellowish-brown t (1 deep red. Cholic acid can also give a brown color with iodine, and, on the other hand, starch is colored brown by iodine in the absence of potassium iodide. Addition of certain salts, potassium iodide for instance, can change the color of starch-iodide to red or yellow. The colors of the starch and its degradation products with iodine is not due to the formation of a chemical compound but to an adsorption in which the color depends on the degree oi dispersity of the substrate,” p. 153. “When cellulose is dissolved, in ammoniacal copper oxide for instance, the crystals remain but they are no longer parallel, and the X-ray diagram [of the precipitated fiber] indicates irregularly arranged crystals. This accounts for the lesser strength of artificial silk and for its unsatisfactory behavior when washed. I t has now been found possible by drawing (as in wire-drawing), pressing, and stretching, to make the crystals in artificial silk lie a little more nearly parallel, thereby improving its properties,” p. I 5 7 . “Hattori was able to show that cholesterin forms an optically homogeneous colloidal solution in swollen lecithin. Water splits this into its components, lecithin and cholesterin, while physiological saline solution has no effect. Saponin coagulates swollen lecithin and breaks down the colloidal solution of cholesterin in lecithin,” p. 161.

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“Morgenroth and Pane heated cobra poison in N/20 hydrochloric acid and tested its haemolytic action immediately after neutralizing and cooling. The haemolytic action, as tested by means of lecithin, proved to have been decressed very much; but came back slowly in time (hours and days) to its original strength. I t seems probable to me that this gradual return of poisoning power after neutralization is an ageing phenomenon. I n the molecularly dispersed cobra haemolysin, particles clumped together gradually to form larger agglomerates with increased adsorbing powers,” p. 220. “Degradation products of albuminoids are poisonous to the organism and especially those formed in the higher organisms create symptoms very similar to anaphylactic shock and also similar physical changes in the blood,” p. 236. The most general phenomenon of the later development of the organism, namely of ageing, is dehydration. Gels show it in a shrinking, a decrease of permeability for dissolved salts, and a decrease in elasticity. With sols, such as protoplasm, one recognizes it in a decrease of dispenity and of viscosity. There is also a decrease in the protective action. As people grow older, lime salts and urates precipitate more readily in the organism. It is also no mere accident that sickneases, which act similarly on the body colloids, give the organism the appearance of extreme old age,” p. 241. “Under pathological conditions the water content of the organism may attain to much higher values than is normal. In severe anaemia the water content of the blood may increase ninety percent and more, while in diabetes the value may sink from 73.2 to 66.5%. In the case of Diabetes insipidus, there may be a flow of twenty or more liters of urine per day. Other organs may show abnormal swelling under pathological conditions. In fever, along with the intense conversion of organic matter into crystalloid products, there are also changes in swelling (thirst, dryness of the skin), about which we have little real knowledge. “In general there has been less study of the cases in which swelling of the organs is less than the normal. Through injection of protoplasm poisons (many salts of the heavy metals, strong acids) a coagulation of the organic albumin may be brought about, whereby the swelling powers are decreased more or less. The most important factor for the distribution of water is the actual reaction of blood and tissue. In general one can say that alkalosis is connected with water retention and acidosis with a shrinking of the tissues,” p. 251. “Hoeber has suspended blood corpuscles in dilute isotonic solutions of different alkali salts and has observed the order which facilitates the coming our of the haemoglobin. The following order was obtained: S04