296 



SCIENCE. 



[Vol. XIII. No. 324 



The antiquities of the country do not consist of such great pyra- 

 mids as those of Xochicalco, or the palace of Palenque, but they 

 possess a peculiar style of their own, and afford important material 

 for reconstructing the ancient history of Mexico. They are diffi- 

 cult to find, for since the days of Cortes the primeval forest has 

 completely covered and buried them. The houses of the ancient 

 inhabitants stood upon raised foundations, consisting of small 

 pyramids of regularly hewn stones. Among these heaps of stones 

 the largest trees of the virgin forest have expanded, and separated 

 the stones from one another. During the construction of railways, 

 a large number of these pyramids were opened ; and in this way a 

 quantity of household furniture has been found, especially painted 

 pottery, and statuettes of beautiful forms, and made of excellent 

 material. The tropical rains also bring to light many objects of 

 the same kind. 



Dr. Seler then visited the territory of the Zapotecas, in the state 

 of Oaxaca. The condition of this region is considerably more ad- 

 vanced than that of the country of the Huaxteca. The land is 

 richer and better cultivated, the villages better built. Intellectually 

 it is the most advanced state of the republic. The numerous val- 

 leys which cut into the high lands, and the numerous rivers which 

 have to be crossed, present special difficulties to the development 

 of trade and commerce. In many cases the river-bed itself forms 

 the road ; and in the rainy season, from August to October, inter- 

 course is often interrupted for months at a time. 



The territory of the Zapotecas is the land of mounds and bas- 

 tions. These have partly served as fortifications, partly as tombs, 

 many of which remain to be opened, for the law which prohibits 

 the exportation of antiquities is only too well calculated to discour- 

 age explorers. Here Dr. Seler discovered numerous inscriptions 

 and important paintings which had escaped the notice of former 

 observers. The hieroglyphics discovered on the national sanctu- 

 aries of the Zapotecas may, should they be completely deciphered, 

 afford a key to the proper understanding of the connection between 

 4he Maya and Aztec civilizations. 



HEALTH MATTERS. 

 Baking-Powders. 



Professor J. W. Mallett of the University of Virginia has 

 recently made a series of experiments with alum baking-powders, 

 and studied effects upon digestion of the residues left therefrom in 

 bread. A full report has been published in the Chemical News. 

 He says that it has been almost universally conceded that alum it- 

 self, when added singly to bread or other food, is positively injuri- 

 ous to health ; and that its use, even in the small proportion some- 

 times employed to improve the appearance of bread made from 

 unsound or inferior flour, must be regarded as reprehensible. But 

 since the extensive introduction, in the United States, of baking- 

 powders made with alum and bicarbonate of soda, there has been 

 much dispute as to the harmlessness or harmfulness of the sub- 

 stances which are left in bread made with such powders after the 

 mutual re-action of their constituents and the completion of the 

 baking process. 



It has been claimed, by those who advocate the use of cheap 

 baking-powders made with alum as one of the ingredients, that as 

 soon as the mixture of alum (usually first deprived, by heating, of 

 the whole or much the greater part of its water of crystallization, 

 — so-called "burnt alum ") and bicarbonate of soda is moistened, 

 as in working it up with flour to form dough, the aluminum sulphate 

 is decomposed, sodium sulphate being formed, with which there 

 also remains sulphate of ammonium or potassium, as ammonia or 

 potash alum has been used ; and the aluminum assumes the form 

 of aluminum hydroxide, insoluble in water, and therefore supposed 

 to be inert and harmless in the stomach and alimentary canal. It 

 has been noticed that the aluminum is also partly converted into 

 phosphate in presence of the phosphates naturally occurring in 

 flour, and this has been also taken to be insoluble and inert. It 

 has been further claimed, that, at the temperature of the baking- 

 oven, aluminum hydroxide is itself decomposed, water being given 

 off, and the highly insoluble aluminum oxide, or alumina, left be- 

 hind, to be discharged from the intestines as might be so much 

 clay or other harmless and indifferent matter. 



On the other hand, it has been asserted, by some of those who 

 oppose the use of alum in baking-powders, that the decomposition 

 is not, or may not be, complete, and in any case, that, as all of the 

 constituents of the alum remain in the bread, the action upon the 

 human system must be essentially the same as if the alum itself 

 remained intact. 



In the discussion of the effects on health of the residual sub- 

 stances left in bread made with alum baking-powders, there has 

 been a good deal of loose argument, based upon data which were 

 either merely assumed as probable, or were too imperfectly sup- 

 ported by actual experiment. In such experiments as have been 

 hitherto recorded, bearing directly on the question, there are many 

 points left in an indeterminate state, and calling for further inves- 

 tigation in order to clear them up and admit of an impartial con- 

 clusion being reached. The work undertaken by Professor Mallett 

 was with a view to furnish some more exact and satisfactory evi- 

 dence of the kind required for the purpose of reaching such a con- 

 clusion. 



In the examination, twenty-seven samples, representing seventeen 

 brands, were analyzed. Nearly all contained as their acid ingre- 

 dient a mixture of alum and acid phosphate of calcium (" super- 

 phosphate "). All contained as the alkaline ingredient acid car- 

 bonate of sodium (" bicarbonate of soda "). After a most thorough 

 and painstaking inquiry into the whole subject, he reached the fol- 

 lowing conclusions: i. The greater part of the alum baking- 

 powders in the American market are made with alum, the acid 

 phosphate of calcium, bicarbonate of sodium, and starch ; 2. These 

 powders, as found in retail trade, give off very different propor- 

 tions of carbonic-acid gas, and therefore require to be used in 

 different proportion with the same quantity of flour, some of the 

 inferior powders in largely increased amount to produce the 

 requisite porosity in bread ; 3. In these powders there is generally 

 present an excess of the alkaline ingredient, but this excess varies 

 in amount, and there is sometimes found, on the contrary, an ex- 

 cess of acid material ; 4. On moistening with water, these powders, 

 even when containing an excess of alkaline material, yield small 

 quantities of aluminum and calcium in a soluble condition ; 5. As 

 a consequence of the common employment of calcium acid phos- 

 phate along with alum in the manufacture of baking-powders, 

 these, after use in bread-making, leave, at any rate, most of their 

 aluminum in the form of phosphate (when alum alone is used, the 

 phosphate is replaced by hydroxide) ; 6. The temperature to which 

 the interior of bread is exposed in baking does not exceed 212° F. ; 

 7. At the temperature of 212° F., neither the "water of combina- 

 tion " of aluminum hydroxide, nor the whole of the associated 

 water of either this or the phosphate, is removed in baking bread 

 containing these substances as residues from baking-powder ; 8. 

 In doses not very greatly exceeding such quantities as may be 

 derived from bread as commonly used, aluminum hydroxide and 

 phosphate produce, or produced in experiments upon himself, an 

 inhibitory effect upon gastric digestion ; 9. This effect is probably 

 a consequence of the fact that a part of the aluminum unites with 

 the acid of the gastric juice, and is taken up into solution, while at 

 the same time the remainder of the aluminum hydroxide or phos- 

 phate throws down in insoluble form the organic substance con- 

 stituting the peptic ferment ; 10. Partial precipitation in insoluble 

 form, of some of the organic matter of food, may probably also be 

 brought about by the presence of the aluminum compounds in 

 question ; 11. From the general nature of the results obtained, the 

 conclusion may fairly be deduced, that not only alum itself, but the 

 residues which its use in baking-powder leaves in bread, cannot be 

 viewed as harmless, but must be ranked as objectionable, and 

 should be avoided when the object aimed at is the production of 

 wholesome bread. 



Quarantine Conference. — The recent quarantine confer- 

 ence which convened at Montgomery, Ala., discussed most thor- 

 oughly the question of yellow-fever in all its aspects. As it was 

 composed of the most experienced sanitarians of the country, many 

 of whom have been repeatedly engaged in fighting yellow-fever 

 epidemics, the conclusions of their deliberations are entitled to great 

 respect and consideration. The method of disinfection as practised 

 at the New Orleans station, by the use of superheated steam in 

 steel cylinders under pressure, was indorsed as being the best 



