TEXT-BOOK OF BACTERIOLOGY. 125 



experiments with pathogenic bacteria had shown that for the as- 

 certaining- of their peculiar qualities it is by no means unimportant 

 into what kind of animal they are inoculated. One and the same 

 micro-organism may display a decidedly injurious action on one 

 kind of animal, while it produces no effect on another, and we will 

 find that in all experiments we must carefully take this circum- 

 stance into account. It is only mentioned here in passing, because 

 it stands in connection with certain observations bearing on the 

 point in question. 



The bacilli of glanders are, as we know, particularly virulent in 

 their action on field mice, while white mice, the animals most fre- 

 quently experimented upon, are quite insusceptible to them. H. 

 Leo has, nevertheless, recentJy succeeded in making them suscepti- 

 ble to glanders by feeding them for a length of time on phloridzine, 

 thereb3 T putting them artificially into a diabetic condition and sat- 

 urating their tissues with secreted sugar. 



In a similar way Bujevid had previously remarked that the 

 'Staphylococcus aureus, which is almost without any effect when 

 applied to the subcutaneous cellular tissue of rats and rabbits, pro- 

 duced a strong suppuration it applied in conjunction with a solution 

 of sugar. 



Arloing and his coadjutors proved that the bacilli of sympto- 

 matic anthrax (" black-leg ") will affect animals otherwise not sus- 

 ceptible to them if mixed with 20$ lactic acid, and in other cases a 

 previous treatment of the tissue with sublimate, carbolic acid, or 

 pyrogallic acid has been found to produce the same result. 



It is true that the matter is not so clear and simple here as in 

 the case of Leo's experiments. In them a change was produced in 

 the bodily condition of an animal, enabling bacteria to multiply 

 within it, which they would, under ordinary circumstances, be un- 

 able to do. In the cases which were next mentioned there were 

 probably other factors also in activity, which we have already met 

 with in the toxic micro-organisms i.e., the excretions of the bac- 

 teria introduced were placed in a condition to act deleteriously by 

 being united with other chemical substances. 



However that may be, all these attempts to extend the sphere 

 of activity of the pathogenic bacteria and to increase their viru- 

 lence have one point in common: as soon as the special conditions 

 under which we have placed the micro-organisms cease to act, no 

 further change is noticeable in them. The bacilli of glanders, for 

 instance, which are taken from the tissues of white mice have not 

 attained the capacity to infect animals of the same kind without 

 the previous preparation: they behave just as usual. In other 



