330 A MANUAL OF BACTERIOLOGY 



quinine, a- and yS- naphthol, arsenious acid, sodium 

 arsenite, potassium arsenite, arsenic acid, alcohols, 

 boric acid, certain essential oils, etc. Heat, 

 electricity, and certain gases have also the power 

 of destroying microbes. 



As antisepsis and disinfection play such impor- 

 tant parts in medicine, surgery, and sanitation, it is 

 desirable that greater attention should be paid to 

 the investigation of the action of various chemicals, 

 etc., on microbes than has hitherto been the case. 



CONCLUDING REMARKS. 



We have seen that microbes are omnipresent, 

 being so light in weight they are readily carried 

 over thousands and thousands of miles by air 

 currents without losing their vitality. This is not 

 surprising when we bear in mind that Eome has 

 been showered with the sands of Sahara, France 

 with South American diatoms, and that the volcanic 

 dust from Cotopaxi fell thousands of miles away 

 from the seat of the eruption. If sands, diatoms, 

 and volcanic dust are capable of being carried 

 enormous distances, it is hardly irrational to suppose 

 that microbes may travel from planet to planet, 

 especially the anaerobic forms, and even those 

 which are aerobic are capable of being desiccated 

 without losing their vitality. 



Then again, from these first living germs, in 

 which the peculiarities of the animal and vegetal 

 kingdoms are hardly yet separated, the laws of 



