424 



SCIENCE. 



[Vol. XIII. No. 330 



widely. Unless properly prepared, the acid phosphate may not be 

 so unobjectionable a substance. It is made by acting upon ground 

 bones with sulphuric acid. The result is sulphate of lime and the 

 acid phosphate of lime. If, now, the latter, which is freely soluble 

 in water, is leached out, leaving the sulphate of lime behind, we 

 have the acid phosphate in fit condition to be used. It is mixed 

 with starch, dried, and brought into the market as a cream-of- 

 tartar substitute. Frequently, however, the sulphate of lime is left 

 with the acid phosphate, and will then bring about any ill effects 

 that may justly be attributable to the sulphate. Moreover, unless 

 the sulphuric acid used has been carefully purified, it may bring no 

 inconsiderable quantities of lead, and even arsenic, into the baking- 

 powder. 



Bisulphate of Potash and Soda Powders. 



Bisulphate of potash has been to some extent used in baking- 

 powders. Its ready solubility would render it unsuitable for use 

 alone ; but, when used, it has probably been for the purpose of se- 

 curing a more rapid Uberation of carbonic acid at first. Used with 

 bicarbonate of soda, it leaves a residue of sulphate of potash and 

 sulphate of soda ; and the sulphate of potash is a very objection- 

 able substance, if present in any considerable quantity. Stille and 

 Maisch say of it, " Formerly used as a purgative. It is so in 

 smaller doses than other salines. Its action is apt to be harsh and 

 burning in the abdomen." The dose is one-fourth to one-half 

 ounce. 



The sulphate of soda (Glauber's salt) is also an active purgative, 

 very little used in England or in this country for administration to 

 human patients, but it is used in Germany very largely in place of 

 our more commonly employed sulphate of magnesia (Epsom salts). 

 The dose of sulphate of soda as a purgative is one-half ounce to 

 one ounce, from which it appears that it is a much more active 

 drug than Rochelle salt. 



Bisulphate of soda has been used in baking-powders, in com- 

 bination with other acid principles. Its action on bicarbonate of 

 soda results in a residue of sulphate of soda. The effects of such 

 a residue will be referred to under alum-powders. 

 Sesqui-Carbonate of Ammonia. 



Carbonate of ammonia, used in small quantities, is perhaps un- 

 objectionable ; but probably, if any considerable quantity were 

 employed, disagreeable physiological effects might be expected, 

 irrespective of the unpleasant odor and taste that the ammonia 

 compounds would impart to the bread, which always shows am- 

 monia re-action, even when small quantities only were used in 

 making it. The ammonia salts in general appear to be much 

 more irritating and stimulating than the corresponding soda or 

 even potash salts. Stills and Maisch say of carbonate of ammonia, 

 " It is irritant, and if long continued, even in doses which the 

 stomach will tolerate, it impairs nutrition." In doses of five to ten 

 grains, it increases the fulness and force of the pulse, and causes a 

 sense of tightness in the head. It is a very powerful agent. The 

 ordinary dose is two to ten grains. Evidently, such a substance 

 needs to be used with care in preparing foods. 

 Alum Baking-Powders. 



Of late years the alum baking-powders, being more cheaply 

 made, have come into extensive use, and have met with consider- 

 able opposition on the score of qualities alleged to be injurious to 

 the health. The alum used in this part of our country is now al- 

 most exclusively burnt ammonia alum ; and, since the potash alum 

 is more expensive, the same is probably true of alum baking-pow- 

 ders in general. The crystallized alums are less frequently em- 

 ployed, because they are too easily soluble ; but they may be used 

 in connection with the burnt alum, to secure at first a more rapid 

 escape of carbonic-acid gas. The alumina is present in the bread, 

 partly as hydrate and partly as phosphate of alumina, in case 

 simple alum baking-powders are used. Where acid phosphates 

 are also used in sufficient quantity, the alumina remains in the 

 bread as phosphate. 



Professor Mallett regards it as a fair conclusion 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 

 he production of wholesome bread. 



Tartaric Acid and Tartrates in Alum-Powders. 



The makers of alum baking-powders sometimes add tartaric acid 

 or bitartrates to their powder, either with or without the addition 

 of acid phosphate of lime. This is doubtless done with the best 

 intentions, either to secure a more rapid escape of carbonic-acid 

 gas at the outset, or otherwise improve the powder. Such addi- 

 tions in the case of several samples have been found, but the pres- 

 ence of tartaric acid or tartrates in alum-powders is very objec- 

 tionable. If added in sufficient quantity to otherwise pure alum- 

 powders, they prevent the precipitation of the insoluble hydrate of 

 alumina entirely when the powder is boiled with water, and they 

 may render much of the alumina soluble in water even after the 

 bread is baked. Without doubt, it would then be readily soluble 

 in the digestive organs, producing there the effects due to alum or 

 any other soluble aluminum compound. Not even the boldest ad- 

 vocates of alum-powders have denied the injurious tendencies of 

 soluble aluminum compounds in the bread. 



Acid Phosphates in Alum-Powders. 



The addition of acid phosphate to alum-powders can only be 

 regarded as an improvement, provided the acid phosphate is free 

 from sulphate of lime, lead, or other objectionable substances, and 

 the powders are put up in truly air-tight packages. Otherwise the 

 deterioration leads to the use of larger quantities of the powder, 

 and often with the result of introducing larger quantities of the 

 alumina compounds into the bread. 



Results of Analysis. 



The following tables give the results of analysis of the samples, 

 so far as was necessary to classify them and determine their 

 " strength ; " that is, the percentage of carbonic-acid gas. The 

 cubic inches of gas are given from one ounce avoirdupois of pow- 

 der, at a temperature of 60° F., and barometer at thirty inches. 



/. Cream-of-Taria7- Powde^-s. — In this class are placed all 

 powders giving re-actions for tartaric acid and potash, and free from 

 the phosphates, alumina, and any considerable quantity of soluble 

 sulphates. Ammonia was sometimes present, whether as sesqui- 

 carbonate or bitartrate was not determined. Free tartaric acid 

 was found in one case. Its presence has no effect on the whole- 

 someness of the powder, nor has the small amount of ammonia in 

 any case found. The writer's experience is that the powders free 

 from ammonia compounds yield just as light biscuits, etc., as the 

 others. As regards purity of materials, there seems little choice 

 between the higher grades of these powders. 



//. Acid-Phosphate-of-Lime Powders. — The first two of these 

 were packed in tightly corked glass bottles, and contained enough 

 starchy material to keep them from deteriorating in these bottles. 

 The bread preparation consisted of two separate powders, each in 

 a paper package. One was bicarbonate of soda ; the other, acid 

 phosphate of lime mixed with^ starch. The strength was deter- 

 mined on a mixture of the two in the proportions directed on the 

 packages. The wheat-powder was put up in tin boxes, without 

 starch or other filling. One sample was in excellent order ; the 

 other, much caked. 



///. Alum and PJiosphate Powders. — This class embraces 

 powders showing ammonia, soluble sulphates, alumina, and phos- 

 phates, when tested as already described. Inasmuch as some of 

 these powders showed considerable alumina in the simple water 

 solution, a more detailed examination of them is recommended, for 

 the reasons already given. The actual presence of acid phosphate 

 of lime, or of any other acid phosphate, was not proven ; but all 

 contained some phosphate, and have therefore been classed as in- 

 dicated, although probably in every case they were made with acid 

 phosphate of lime. As already m,entioned, the low grade of several 

 is perhaps from deterioration, due to the presence of the acid 

 phosphate in packages not sufficiently air-tight. Acid phosphate 

 will not keep well when mi.xed with bicarbonate of soda, except in 

 well-corked bottles. Tin cases are not tight enough. Many of 

 these powders contained sulphate of lime, chemically equivalent to 

 ierra alba. This was, perhaps, in no case added as an adulterant, 

 but was a part of the acid phosphate of lime used ; the latter not 

 having been separated from the sulphate of lime formed in its 



