1886.] Larva of Smerinthus ocellatus and its Food-plants. 135 



to coagulate, and when the quantity injected is insufficient to kill, the 

 blood (drawn off after injection) may remain uncoagulated for some 

 days. In either case coagulation of shed blood may be induced by 

 the addition to it of the liquid which has been injected. It therefore 

 appears that the agent which brings about coagulation, intra -venas, 

 must disappear in the act of coagulation. The shed blood contains 

 only a minute trace of fibrin ferment. 



The acetic acid precipitate is soluble* in 0'5 per cent. HC1 solution. 

 On digesting this solution at 37°, after the addition of pepsine, a part 

 of it is converted into peptone, but a precipitate appears in the pro- 

 cess which is permanent. When the digestive products (peptone 

 and precipitate), having been rendered alkaline, are injected into the 

 circulation, no effect is produced.f There is neither intravascular 

 coagulation, nor is the blood deprived of its power of coagulation ; 

 but if fresh acetic acid precipitate be added to the liquid, both effects 

 follow injection. Consequently, the failure of effect when the pro- 

 ducts of digestion are injected alone, is not due to presence of pepsine 

 or peptone. I have ascertained that the acetic acid precipitate does 

 not cause coagulation of dilute magnesium sulphate plasma, which 

 coagulates readily on the addition of fibrin ferment. The agent, 

 therefore, in producing intravascular coagulation cannot be identified 

 with that body. 



II. " A Further Enquiry into a Special Colour-relation between 

 the Larva of Smerinthus ocellatus and its Food-plants." 

 By Edward B. Poulton, M.A., of Jesus and Keble 

 Colleges, Oxford. Communicated by Professor J. 8. 

 Burdon Sanderson, F.R.S. Received January 26, 1886. 



CONTENTS. page 



1. Introductory 135 



2. Experiments upon the Larvae of Smerinthus ocellatus during 1885 138 



3. The General Results of the Breeding Experiments 153 



4. Observations in the Field upon Larvae of Smerinthus ocellatus during 1885 157 



5. Experiments upon Captured Larvae 159 



6. Conclusions arrived at by the Consideration of the Captured Larvae : the 



Reconciliation of Conflicting Evidence 159 



7. The whole of the Evidence Summarised ltJ5 



8. Conclusion 172 



1. Introductory. 



In my previous paper upon this subject (" Proc. Roy. Soc," No. 237, 

 1885, p. 269), I gave an account of some breeding experiments under- 



* As casein is " soluble" in milk. 



f The total quantity of peptone is very small. 



. L 2 



