ADDITIONS AND NOTES TO VOL. I. 475 



the blood of carnivorous animals which crystallises in prisms, while 

 the corresponding substance in the blood of guinea-pigs and rats 

 crystallises in tetrahedra. This obviously points at combinations 

 of an analogous kind, in which only one different constituent has 

 entered, which, however, is the cause of the difference in the 

 crystalline form of the otherwise perfectly analogous body. Thus, 

 for instance, according to Rochleder's hypothesis, one of these 

 bodies might contain methylamine and the other ethylamine, in 

 combination with the same group of atoms. We are, however, 

 still deficient in the data which are requisite for the further 

 elaboration of such an hypothesis, partly because the protein- 

 bodies have as yet been little investigated in relation to these 

 views, and partly because their decompositions, in so far as they 

 are yet known, do not enable us to arrive at any definite con- 

 clusions on these points. 



(34.) Addition to p. 332, line 9. Panum* has contributed 

 many important facts to our knowledge of the albuminous bodies 

 and of their various reactions, and he has done much to correct our 

 views regarding the coagulation of albumen and of similar matters 

 by heat. He has especially shown, by numerous and very careful 

 experiments, the influence exerted by the presence of salts or 

 small quantities of acids on the separation of the protein-bodies 

 at high temperatures. He found, for instance, that as a general 

 rule, the temperature at which precipitation takes place is low in 

 proportion to the amount of salt that has been added, and that the 

 quantity of acid which is requisite to produce a permanent precipi- 

 tation at the same temperature, is inversely proportional to the 

 quantity of salt that has been added to the solution of albumen. 

 Panum thinks that he is justified, from these and similar experi- 

 ments, in considering all our previous ideas of coagulation as " con- 

 fused ;" but this conclusion is most distinctly to be drawn from his 

 experiments, namely, that we must very carefully distinguish 

 precipitated albumen from coagulated albumen. It appears, from 

 my observations, that alcohol acts in relation to the precipitation 

 and coagulation of albuminous matters in the same manner as the 

 salts in Pan urn's experiments. By the gradual addition of alcohol 

 we can depress the coagulating point of the fluid step by step, 

 till we arrive at a point where the albuminous substance is pre- 

 cipitated, although not coagulated; and then, if not soluble in 

 water, it still dissolves in solutions of the neutral salts of the 

 * Arch. f. path. Anat. Bd. 4, S. 17. 



