530 



Mr. E. C. Hort. 



[June 2, 



Loss of Weight. 



6. Selection of a species of animal, such as the guinea-pig, on which, 

 reliable observations as to weight can be made for several days previous and 

 subsequent to injection in order to establish necessary control. 



7. Exclusion of error owing to any loss of weight being due to refusal of 

 the animals to take food after injection. 



Hise in Antitryptic Values of Serum. 



8. Demonstration of the accuracy of the method used to measure anti- 

 tryptic values. 



9. Demonstration of strict parallelism between the antitryptic values of 

 the serums of normal individuals of the species of animal injected. 



The precautions requiring further detail are those inimbered 3, 4, 5, 7, 8, 9. 



3. The mean average temperature of 135 guinea-pigs selected for experi- 

 ment was 101"4° F., or 38"6° C, the upper normal limit of temperature being^ 

 102"2° F., or 39° C. The mean average, temperature of 50 apparently healthy 

 rabbits was 102-4° F., or 39-1° C, the upper normal limit of 103° F., or 

 38-6° C, usually assigned, being accepted. 



4. Repeated handling per se was invariably found to produce no rise of 

 temperature in healthy guinea-pigs or rabbits. Unless, however, great 

 gentleness be employed in taking repeated thermometric observations on 

 the guinea-pig, fever is easily induced, owing to slight abrasion of rectal 

 mucous membrane caused by insertion of the thermometer and consequent 

 septic absorption. This does not occiir in the rabbit with ordinary care. 

 Hence the effect of multiple injections involving a series of thermometric 

 observations extending over several days can only be satisfactorily studied 

 in the rabbit. This does not ajjply to the study of the effects of single 

 injections in the guinea-pig, as all observations can^e completed in one day. 

 After injury to rectal mucous membrane tliere is always a latent period of 

 not less than 12 hours before fever caused by introduction of the thermometer 

 appears, whereas the fever caused by injection of water is never more than 

 five houis in reaching its maximum after injection. Hence in animals 

 controlling injections on the first day a rise of temperature is always absent, 

 provided that the animal is healthy. 



5. Neither subcutaneous puncture nor injections of air up to 10 c.c, the 

 maximum quantity of water injected into guinea-pigs in these experiments 

 for tlie (l(!monstratioii of fever, cause any rise of temperature in guinea-pigs. 



7. The loss of weight observed in guinea-pigs after multiple injections of 

 water can be shown not to be due to refusal of tlie animals to take food,. 



