1914] Editoriais 5^5 



leucocytes there is contained a supply of thromboplastic material 

 (phosphatid-compound) and also of Prothrombin. On the shed- 

 ding of blood the disintegration of the platelets and, to a lesser 

 extent, of the leucocytes liberates thromboplastin and Prothrombin. 

 The former neutralizes the antithrombin, the latter, together with 

 the Prothrombin already present in the plasma, is changed to throm- 

 bin by the action of the calcium. The plasma of the circulating 

 blood would remain unclotted when blood is shed were it not that 

 the existing equilibrium is disturbed by the addition of the sub- 

 stances furnished by the disintegrated platelets. Cell-free plasmas, 

 obtained by special means to avoid destruction of the platelets, do 

 not coagulate spontaneously but may be made to clot by the addition 

 of thromboplastin (kephalin). W. H. Howell. 



(Abstract of paper read before the National Academy of Sci- 

 ences last April; presented here by the author at our request. — Ed.) 



Three years ago the Biochemical Bulletin published a paper 



in which the term " lipins" was used to designate, collectively, the 



fats and various substances, such as " lipoids," that resemble fats.^ 



Lipins: a matter of This proposal did not include the rejection of 



terminoiogy " lipoid " ; it involved merely the adoption of the 



term '' lipins'' to represent conveniently the fats and the lipoids, f. e., 

 fats and all iat-like substances. It was suggested, in effect, that the 

 term "lipins" be used in the general way that "proteins" is com- 

 monly employed, i. e., with reference primarily to convenience in 

 description rather than to impossible accuracy in chemical charac- 

 terization. 



One of the recent formal adoptions of the term "lipins" is indi- 

 cated by the f ollowing statement, among others, in Chemical pathol- 

 ogy, by Prof. H. Gideon Wells (1914, 2d ed., p. 23) : "Lipoids is a 

 term in common use but of indefinite significance; most usually it 

 comprehends the intracellular substances which are soluble in ordi- 

 nary fat solvents, but which are not simple fats or fatty acids, 

 lecithin and cholesterol being the most important of the lipoids. 

 For the entire groiip of fats and lipoids the term lipins has been pro- 



1 Biochemical Bulletin, 1911, i, p. 51. 



