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tics. Disinfectants is the common name given to ger- 

 micides and antiseptics. Spores resist the power of dis- 

 infectants longer than vegetative forms. Products of germs 

 (toxins etc.) are generally antagonistic to the growth of 

 germs. But the germs themselves are made up of a pro- 

 toplasmic substance which is highly helpful to the growth of 

 germs. So instead of filtering, if we boil water which is 

 supposed to contain many germs, we prepare only a weak 

 broth in which germs multiply very fast. Between filtering 

 and boiling, filtering should be preferred. But filtered water 

 which is boiled and consumed immediately afterwards is the 

 safest drink. The haphazard direction given by municipali- 

 ties to drink boiled water when any epidemic is raging, is 

 conducive to more harm than good. Ordinary water after 

 it is boiled soon gets a bad smell due to the ready growth of 

 germs in what is practically a weak soup. 



1.293. Some microbes are both parasitic and saprophitic. 

 These are called facultative parasites; <?.., the bacilli of 

 anthrax, cholera and typhoid. Typhoid germs multiply not 

 in cold but in warm water and cholera germs in water con- 

 taining much organic matter. As a rule, however, putre- 

 factive germs do not grow inside living animal tissues, and 

 parasitic germs in water. The bacilli that abound in the 

 intestines are anaerobic and do not grow in the blood until 

 death, when they quickly multiply and help to decompose 

 the corpse. 



1.294. Different species of microbes can subsist in the 

 same substance, such as milk, butter etc. Scalding kills the 

 bacillus lactis in milk but it does not kill certain bacilli which 

 have the power of turning milk bitter instead of acid. Under 

 certain conditions these bacilli may multiply and produce 

 bad taste in milk. Weigmann's bitter-milk bacilli are 

 feebly motile and spore forming bacilli, which sown in 

 sterilized milk give it a very bitter taste, in 24 hours. Cohn's 

 bitter-milk micrococcus has a similar effect on milk. The 



