282 



Dr. L. C. Wooldridge. 



[June 7, 



surface of the skin. It must be understood that this membrane was 

 quite distinct from the amnion. 



The epitrichium, therefore, is present both in the Lemurs and in 

 the Sloths, but in the former it does not, after the hairy coat is 

 developed, form a complete envelope for the foetus, but is broken up 

 before the termination of the period of gestation into more or less 

 detached flakes of membrane. 



III. 11 Note on the Coagulation of the Blood." By L. C. 

 Wooldridge, M.D., M.R.C.P., Co-Lecturer on Physiology at 

 Guy's Hospital. Communicated by Professor Victor 

 Horsley, F.R.S., &c. (From the Laboratory of the Brown 

 Institution.) Received May 24, 1888. 

 In a paper read before the Royal Society, April 26th, 1888, Dr. 

 Halliburton offers some criticism of my views respecting the coagu- 

 lation of the blood. In this note I shall briefly summarise and 

 traverse the objections Dr. Halliburton raises to my theory and expe- 

 riments. 



I. Dr. Halliburton suggests that the substance I call A-fibrmogen 

 —which I obtained by cooling peptone-plasma— is not a normal 

 constituent of the blood plasma, but that it is a precipitate of a 

 hemi-albumose, supposed by him to be present in the peptone 

 which is injected into an animal for the purpose of obtaining peptone 

 plasma. I do not use Witte's peptone, as Dr. Halliburton appears to 

 have done, on account of its recognised impurity, but that obtained 

 from Dr. Gruebler's well-known laboratory in Leipsic. This peptone 

 is prepared according to Henniger's method. A 10 per cent, solution 

 of it in J per cent, solution of sodium chloride is quite clear after 

 filtration. 



It gives no precipitate on cooling to zero. 



It disappears wholly from the blood within one or two minutes 

 after injection. 



Finally, A-fibrinogen has properties absolutely different from the 

 peptone injected. 



Dr. Halliburton appears to think that this substance, A-fibrinogen, 

 exists only in peptone plasma. 



I stated in a paper read before the Royal Society in 1885, " On a 

 New Constituent," &c, that it was also present in salt plasma, and I 

 gave details concerning it in the Croonian MS., which is in the archives 

 of the Royal Society. I explained at length in the paper referred to 

 by Dr. Hallibnrton, and published in Ludwig's ' Festschrift,' 1887, 

 why there are, as has long been known, two varieties of salt plasma, 

 namely, one containing, as I showed, no A-fibrinogen, this being not 



