34 Colonel Sir Almroth E. Wright [March 9, 



staphylococci and streptococci. Since we had on every part of 

 the walls precisely the same amount and kind of bacterial infection, 

 and since we are in each case dealing with the self-same lymph and 

 leucocytes, this difference of results is imputable, not to our having 

 in the lymph leech a different bacterial implantation, but to the 

 negative pressure having furnished a larger proportion of blood fluids. 



But with this the problem is, as you see, only incompletely 

 resolved. We have learned that the corruption of the lymph is not 

 determined by the nature of the bacterial implantation ; we have 

 reason to think it is hindered by a larger afflux of lymph; and 

 it looks as if it might have something to do with the breaking down 

 of the leucocytes. But we have not yet put our finger upon the 

 particular element that takes away from the serum its power of 

 inhibiting microbic growth, and converts it into a congenial pabulum 

 for all manner of micro-organisms. 



Let me in this connexion invite you to consider, for that may 

 perhaps put us on the path for the solution of our problem, a scheme 

 of classification of the albuminous substances. I w^ould propose to 

 classify them from the point of view of their capacity to furnish 

 pabulum for microbes, and to distinguish three classes of albuminous 

 substances. First, would come digested alhiunens. It is familiar 

 matter that these furnish very congenial pabulum for microbes. In 

 the form of peptone we use them for all our artificial cultures. A 

 second category of albumens would be native albumens. Muscle, 

 milk, and eggs furnish such albumens. These are not like digested 

 albumens, directly assimilable. Before they can be assimilated, 

 wliether by ourselves or by microbes, they must be broken down 

 into simpler elements by digestion. To that end we, and a certain 

 number of microbes also, are furnished with digestive ferments. 

 There is yet a third class of albumens. I would venture to call these 

 defended or protected albumens. These cannot, like the digested 

 albumens, be directly assimilated. Nor can they, like the native 

 albumens, be directly digested. They are specially defended against 

 the attack of digestive ferments. The albumens of the serum fall 

 into this class of " defended albumens." It is well known with 

 respect to serum that it has an antizymotic, and in particular an 

 antitryptic, power — a power of neutralizing digestive ferments, and 

 in particular trypsin.* You will, perhaps, not immediately perceive 

 that the fact that the serum is antitryptic in any way elucidates our 

 problem, l^ut let us take that fact and put it in another way 

 and then consider. Let us, instead of saying that tlie serum has an 

 antitryptic property, suy that it has a power of preventing its 



* Let mo here incidentally call attention to the fact that the application 

 of horse serum will prevent and very effectually relieve the digestive erosion of 

 the skin which is in enterostomy of the upper part of the small intestine 

 produced by the outflow of pancreatic juice. 



