MISCHIEF-MAKERS IN MILK. 211 



double, triple, or quadruple, and provided with a system of heat- 

 ing pipes. The steam which proceeds from the boiling juice of 

 the first vessel serves to heat the second vessel, and so on through 

 the entire series. The evacuation of the heating system on the 

 evaporator is effected by means' of small tubes leading from one 

 vessel to the other and connected with a condenser. 



When the sirup has attained to a certain degree of concentra- 

 tion, it is drawn off by means of pneumatic suction direct into the 

 vacuum boiler. The vacuum boiler, Fig. 8, consists of a vertical, 

 cylindrical, or ball-shaped vessel, with a conical base, containing 

 heating worm tubes. The mass obtained from the vacuum boiler 

 is first of all placed in a refrigerator, which consists of a trough 

 provided with a stirrer and a refrigerator jacket. The mass of 

 sugar crystals must now be separated from the sirup, so that raw 

 sugar may be obtained, and hence it is sent forward from the 

 refrigerator to the centrifugal machines. 



A centrifugal machine, Fig. 9, consists of a cylindrical drum, 

 over which is a finely perforated sieve, and which rotates with 

 great rapidity on its own axis. The mass placed in the drum is 

 pressed against the sieve by the action of centrifugal force, and 

 the fluid escapes through the small apertures. The sirup hav- 

 ing been disposed of, the yellow sugar obtained is called the first 

 product, and this, having been emptied from the drum, is trans- 

 ferred to another sieve, where it is freed from the lumps which 

 it may contain, and the raw sugar is finally emptied into sacks on 

 the lower floor, when it is ready for the refinery. The process 

 of refining raw sugar into the block sugar of commerce is an 

 independent industry. 



MISCHIEF-MAKERS IN MILK. 



By ALICE B. TWEEDY. 



VERY recently it was announced by Proust that the bicarbon- 

 ate of soda used as a preservative of milk formed a com- 

 pound particularly injurious to children — i. e., the lactate of soda. 

 There appears to be great danger, in the newly aroused fear of 

 fermentative changes in food and of the baneful products of the 

 busy bacilli, that any vaunted preservative or germicide may be 

 greedily seized upon at once, without thought as to the innocence 

 of its chemical activity. This easy credence in antiseptics seems 

 to be characteristic of the minds that shrink with most unreason- 

 ing fear from every advance in bacteriological research. Not long 

 since, a novelist, more imaginative than scientific, arraigned Science 

 because " the idea of the comma bacillus is more dreadful than 

 that of the cholera." This, as an outburst of ignorance, would be 



