POLYMORPHISM OF MICROBES. 279 
thus obtained the formation of small metastatic 
centres in the kidneys, liver, lungs, ete. The spores 
sent forth hyphae which were able to produce im- 
perfect organs of fructification, but failed to effect 
the formation of fresh spores. Gaffky, Koch, and 
Leber repeated these experiments, and showed that 
the acclimatization of any kind of mould in the 
interior of the system was impossible, whatever might 
be the more or less serious lesions produced by the 
introduction of foreign bodies into the blood of a 
warm-blooded animal. 
Errors caused in Laboratory Experiments by the 
Involuntary Miature of Different Microbes—We 
should be the more cautious about accepting the real 
or apparent polymorphism of certain microbes, since 
the most scrupulous precautions do not always suc- 
ceed in preventing confusion. Of this Klein gives 
the following instances. 
While he was studying the microbe of anthrax in 
his laboratory at the Brown Institution, one of his 
friends was studying canine distemper in an adjoining 
room. This friend injected the blood of a dog affected 
by distemper into a guinea-pig’s veins, and was sur- 
prised to see the animal die two days later with all 
the symptoms of anthrax, and to discover Bacillus 
anthracis in its blood. Yet he had made the injec- 
tion with a perfectly new hypodermic syringe; while 
Klein, for his own injections, had made exclusive use 
of pipettes drawn toa point in the flame of a lamp. 
