362 



The Philippine Journal of Science 



1915 



Table XIII. — Liquefaction of the media due to liquefying bacteria at a 



Filipino tannery. 



Description of sample. 



Days to liquefy 



with one loopful 



of sample. 



Serum. Gelatin. 



River water used for washing hides 

 Do 



Do_._ _-- 



Lime liquor 2 days old 

 Do 



Lime liquor 1 week old 



Native tan liquor 1 month old . 



Native tan liquor.. 



Do 



20 

 6 



Native tan liquor, strong from covered pit 



Fresh tan liquor I 



Artesian-well water as delivered at tannery I 



Suspender liquor (my experiment) mixed with 10 per cent native tan liquor ._j 

 Do 



Liquor from layer No. 1 (my experiment) » 



Do.. 



Liquor from layer No. 1 (my experiment), from covered pit. 

 Fresh tan liquor made with artesian water 



2 

 2 

 8 

 8 

 15 

 3 

 6 



15 



10 



* In this case the workmen were allowed to contaminate the liquor by wading in it with bare 

 feet still wet with liquors from poluted vats, according to the usual practice. Contrast the three 

 days required to liquefy the serum with the following experiment where thirteen days were 

 required. The only difference is that in the second case I insisted that the workmen first wash 

 their feet in clean water before entering the vats. 



The data demonstrate that the tan liquors of the Filipino pro- 

 cess generally contain abundant putrefying or liquefying bac- 

 teria. Even in the case of pelts that had been washed in 0.5 per 

 cent phenol baths, liquefaction ensued within forty-eight hours 

 when immersed in such liquors. The smell of the leather and 

 tan liquors is due to this putrefaction. 



Infusions of fresh camanchile tan bark in pure water are gen- 

 erally practically devoid of liquefying bacteria, as liquefaction 

 of inoculated serum and gelatin media occurs only after from 

 forty-two to seventy-five days of incubation. However, the in- 

 fusion of this tan bark is quite neutral in its action toward 

 liquefying bacteria. It does not kill them. On the other hand, 

 bacteria do not grow in it except when there is enough proper 

 nourishment present in the form of other suitable substances. 

 In the latter case the multiplication and activity are great in 

 a warm climate. 



The tannins, like common salt, do not destroy bacteria, but 

 check the putrefaction of hide substance. Common salt prevents 



