THE PTOMAINES AND SOLUBLE FERMENTS 321 



ID addition to the ptomaines, there are the 

 enzymes and albumoses, which are chemical prin- 

 ciples, excreted by microbes and allied fungi, or the 

 products of the activity of other living cells, e.g. 

 those of the glands of the stomach, pancreas, etc. 

 Such soluble ferments or enzymes as pepsin, 

 ptyalin, trypsin, diastase, invertin, and emulsin are 

 well known to physiologists and chemists. It is 

 not, however, these bodies which we intend to 

 describe, but the albumoses produced by living 

 microbes. In small doses these albumoses are pro- 

 tective; and they appear to be the protective 

 principles in most vaccines. 



'The albumoses produced by microbes resemble 

 those formed during normal digestion in being 

 poisonous when injected directly into the circula- 

 tion, although they may not be so greatly absorbed 

 from the intestinal canal. One of the most remark- 

 able discoveries in regard to albuminous bodies is 

 the fact that some of them which are perfectly 

 innocuous, and, indeed, probably advantageous to 

 the organism in their own place, become most 

 deadly poisons when they get out of it. Thus the 

 thyroid and thymus glands, which are perfectly 

 harmless and probably useful, were found by 

 Wooldridge, when broken up in water, to yield a 

 proteid which instantaneously coagulated the blood 

 if injected into a vein, so that the animal died as if 

 struck by lightning; while Schmidt-Mlihlheim, under 

 Lud wig's directi on, found that peptones had an exactly 

 opposite effect,and prevented coagulation altogether.' 1 



1 Dr. Lauder Brunton in Nature, vol. xliv. (1891), p. 330. 

 X 



