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Scientific Proceedings (68). 



intraperitoneally three times, and tested its serum against cat 

 liver. The action of the serum after the series of injections had 

 increased so that the specimens exposed to a dilution of I : 60 

 resembled histologically the ones previously exposed to 1 : 30, 

 etc. The action on the spleen was not nearly as marked. 



The serum of a rabbit, injected with Beebe's nucleoproteids 

 derived from dog thyroid, at a dilution of 1 : 5 had a much more 

 striking action on the fresh dog thyroid than on the dog spleen. 



As to the exact interpretation of these changes: They cannot 

 be attributed to bacterial action as toluol was always added in 

 abundant amounts and we have found that not infrequently 

 bacteria failed to grow on culture media when they were kept in 

 the same incubator owing to the evaporation of the toluol. More- 

 over, in a series examined at intervals of ten minutes, we have 

 found that at the end of an hour, the changes in the histologic 

 appearance of the sections were quite marked; a period of time 

 too short for bacterial action to have taken place. We have also 

 been able to show that while inactivation at 55 0 C. for one hour 

 failed to destroy this activity of the serum, exposure to 65 0 C. 

 for one half hour led to complete loss of activity. 



From the appearance of the specimens, it is my belief that a 

 number of ferments might be concerned in the production of these 

 striking changes, not only proteases but also peptases and perhaps 

 esterases and nucleases. Sodium fluoride in 0.3 per cent, solution, 

 which is a specific inhibitor of esterase action seemed to weaken 

 the activity of the serum. With normal serum extracted by 

 chloroform according to the method advised recently by Jobling, 

 we have not obtained uniform results. When the serum after 

 filtration remained turbid, as was often the case, no action on the 

 tissue was demonstrable. This activity of the serum is apparently 

 not identical with that of trypsin. With the latter, there is 

 marked fragmentation of the sections at a time when nuclei are 

 still visible. While the present investigation was in progress, 

 there appeared a brief preliminary communication in the Mxiench- 

 ener medicinische Wochenschrift, No. 37, 1914, by H. Rollett, 

 describing a method by which bits of boiled placenta were exposed 

 to serum, then examined histologically. Very meager details are 

 given. 



