490 



Journal of Agricultural Research voi. xiir, no. io 



OBSERVATIONS ON RESULTS OF EXPERIMENTS 5 AND 21 



The following observations on the results of experiment 5 (Table V) 

 are true of the other experiments in which trypsin was used. 



Mixture a. — ^This mixture contained only the serum and was always 

 used as the standard with which the other mixtures were compared. 

 Such a mixture undergoes very little change on standing and may be 

 regarded as having a constant chemical composition and potency for 

 periods such as those indicated in Table VII. All the mixtures vvere 

 prepared under conditions assuring sterility. Bacterial action in the 

 mixtures was prevented by chloroform. The results of mixture A 

 served to standardize the technic of the experiments. For example, 

 if the toxin used had undergone a loss in toxicity, it would have been 

 apparent from results with this mixture. One test was made with a 



standard tetanus anti- 





"O/iYS 



/7 



7e 



toxin, T17, furnished 

 by the Hygienic Labo- 

 ratory. Twelve guinea 

 pigs were used, two on 

 each dose, each of 

 which received o. i unit 

 of the standard anti- 

 toxin plus the follow- 

 ing doses of toxin: 

 Toxin F4; 0.00065, 

 0.0007, ando.ooo75gm. 

 Toxin Fi : 0.00065, 

 0.0007, and 0.00075 

 gm. The results indi- 

 cated that at the time 

 of this test (experiment 4, May i8, 1917), the standard antitoxin and toxin 

 were of standard strength, and the experimental technic used was correct. 

 Mixture b. — This contained serum in 0.5 per cent sodium-carbonate 

 solution. (The mixture B for experiment 6-6.1 contained antitoxin X 

 in a final concentration of N\2i5 sodium hydroxid instead of the carbo- 

 nate. The two solutions are equally alkaline.) In this mixture the 

 antitoxin was slowly but completely destroyed by the sodium carbonate 

 (or hydroxid). After 18 days' contact between the antitoxin and alkali 

 (experiment 5) 91 per cent of the antitoxic units had disappeared; but 

 during this time the data for total coagulable protein and amino nitrogen 

 indicate that the protein contents of this mixture underwent no change. 

 It would appear that in this way the antitoxin may be separated from the 

 associated protein, but during the separation the antitoxic units are 

 destroyed, leaving the proteins intact. This effect was not recorded by 



Fig. I.— The destruction of tetanus antitoxin ( X — ) in 0.5 percent 



sodimn-carbonate solution withoutany change iii total coagulable pro- 

 tein ( O ) or amino nitrogen ( 1 ). Mixture B, experi- 

 ments 4-5.1. 



