103 
oj Edinburgh , Session 1869 - 70 . 
the lymph-hearts of the frog maintain a normal rate long after 
paralysis of the blood-heart.* 
From these results it is apparent, that the primary action of the 
Kombi arrow-poison is isolated in the heart, and that it may there¬ 
fore be included in the class of the cardiac poisons ,—a class of 
poisons whose action has been most accurately defined by the 
researches of Kolliker, Yulpian, Pelikan, Hammond and Weir 
Mitchell, Hilton Fagge and Stevenson, Holme, Dibkowsky, and 
others. 
5. On Thebo-lactic Acid. By J. Y. Buchanan, M.A. 
Thebo-lactic acid was discovered in Turkey opium by Messrs T. 
& H. Smith, the eminent morphia manufacturers of this city. It 
was examined by Stenhouse, and found to have the same composition 
as lactic acid, from which, however, it was supposed by the Messrs 
Smith to differ in the crystalline form of its copper and morphia 
salts. At present we are acquainted with three isomeric lactic acids, 
two of them differing from each other chemically, whilst the third 
is distinguished by its power of rotating the plane of polarisation 
of light. The last named acid, having been but recentlyf discovered, 
it is impossible to say whether it possesses any decidedly distinctive 
chemical properties or not. The other two, namely, the ordinary 
or ethyliden—and the ethylen-lactic acids, possess perfectly distinct 
chemical properties, determined by the different relative position 
in each of the alcoholic hydroxyl. The following rational formulae 
express the different constitution of the two acids :— 
ch 3 
CHOH 
COOH 
Ordinary lactic acid. 
CH.,OH 
ch 2 
COOH 
Ethylen-lactic acid. 
They may be distinguished at once by replacing in each the 
alcoholic hydroxyl by chlorine. We thus obtain from ordinary 
lactic acid the so-called a-, from ethylen-lactic acid, the /3- chloro- 
* The author is indebted to Professor Sharpey of London for an account 
of some experiments made with this poison in 1862. The results mentioned 
in the above abstract harmonise in the most satisfactory manner with those 
obtained by Professor Sharpey. 
t Berichte der Deutschen Chem. Ges. 1869, 620. 
