1 64 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



let the two gradually mix. If physiologically active HC1 is 

 present, even in very small amount, a transient pink colour 

 will be produced.* 



Lactic acid usually occurs in the absence of free hydro- 

 chloric in cancer of the stomach, but its presence is in itself 

 a fact of little value, since it occurs in other conditions. To 

 test for it in a vomit it is necessary to extract the acid by 

 thoroughly shaking up some of the fluid with ether, pipetting 

 off the latter, and then allowing it to evaporate. The acid is 

 contained in a state of comparative purity in the residue, 

 which is then dissolved in water and tested in the following 

 way : To half a test-tubeful of i in 40 carbolic add one or two 

 drops of liq. ferri perchlor. A fine amethyst colour will result, 

 and will be changed to a bright canary-yellow on the addition 

 of the solution of the ethereal extract, if the latter contains 

 lactic acid. It is not sufficient to apply this test to the filtrate 

 of a vomit direct, although this is permissible in the case of 

 the fluid removed from the stomach after a test meal. It is 

 useless to apply it to vomit containing much milk, as this 

 often contains abundant lactic acid. 



The vomit in cases of simple dilatation of the stomach usually 

 contains a variety of bacteria, yeasts, etc., but the most char- 

 acteristic organisms are the sarcinse, a group of cocci which 

 have very definite microscopical characters. They have the 

 property of dividing" by three successive divisions in the three 

 planes of space (at right angles), and the eight resulting cocci 

 do not completely separate from one another. The result is 

 the formation of a group of eight cocci which form one mass, 

 having the shape of a bale of soft material tied round by three 

 tightly drawn cords at right angles to one another. Succes- 

 sive divisions take place parallel to these, and a very complex 

 colony results. The sarcinse, as a rule, are decidedly larger 

 than ordinary cocci, though not as large as yeasts; the 

 different cocci of each group usually vary in size amongst 

 themselves, the younger forms being the larger. Most of 

 them stain by Gram,, but this test is hardly necessary, as 

 they may be readily recognized in unstained wet prepara- 

 tions. 



* Where there is a great excess of proteids this reaction may not succeed , 

 even though physiologically free HC1 may be present. But I do not think 

 this occurs with an ordinary test meal. 



