Db. W. Wallace oa the Chemistry of Sugar Rejirmuj. 37 1 



with the vegetation of a microscopic plant resembling yeast, and that 

 the alteration of a solution of pure sugar into fructose, and vdtimately 

 into glucose, as ah'eady noticed, might be owing to the same agency. 

 On examining a specimen of smeary syrup with a microscopic power of 

 200 diameters, I found numerous protophytes, mostly of a green tint, 

 but some brown. These consisted of single cells, enclosing frequently 

 smaller cells ; and some were seen burst at one side, with the smaller 

 organisms making their escape. I did not perceive any ciliary motion 

 in any of these bodies ; but probably the viscid natm'e of the liquid 

 tended to check the exertion of the ciliary force generally observed in 

 these protophytes at a particular stage of their existence. I have since 

 examined several specimens of smeary syrup, and of grape and fruit 

 sugar solutions formed in the manner already described, and have in all 

 cases found abundance of these protophytes, mostly of the commoner 

 sorts. I do not presume to state that these plants are the true cause 

 of the production of smear ; but I think that this is by no means im- 

 probable. The occurrence of smear in a sugar-house is almost always 

 the result of want of cleanliness, and nothing will produce it more 

 rapidly than having dirty spars of wood in the char cisterns and 

 elsewhere. In like manner, a piece of wood kept moist with water, 

 and at a temperature of 60°, or upwards, soon acquires a " confervoid " 

 odour from the growth of a similar class of plants in the water surround- 

 ing it. Again, sulphurous acid, which is well known to be inimical to 

 vegetable life, is one of the few chemical agents which check the ravages 

 of this fermentation, and this substance is now largely employed, 

 generally in the form of bisulphite of lime, both in the beet sugar 

 factories of France and Belgium, and in our own colonies. It is to be 

 regretted that the sulphate of lime thus produced exercises a prejudicial 

 influence upon the charcoal of sugar refineries. A sugar-house in which 

 a tendency to smear begins to show itself should be at once fumigated 

 with sulphurous acid, as the best means of checking the advance of 

 fermentation ; but there is little danger of this occurring where every- 

 thing is clean and orderly, and the liquors are not kept too long. 

 The old system of treacle pots is a very absurd one, and should in 

 every case be discontinued, and the pots replaced by copper gutters. 



It is but too well known to sugar refiners that molasses, apparently 

 good, frequently give a perfectly uudrainable mass when boiled down. 

 This seems to depend in many cases simply upon the presence of an 

 undue amount of fruit sugar, together with acid, by which the quantity of 

 fruit sugar is greatly increased in the boiling. In other instances brought 

 under my notice, this explanation was inadmissible, and the undi'ainable 

 nature of the resulting " bastards " must have been owing to the 



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