The Minute Structure of the Vinegar Plant. 245 



The bacterium bodies probably give rise to the tough, 

 mucus in which they are involved, and the unorganized mass 

 in which they are embedded in the vinegar plant may only differ 

 in density from the more delicate material in which the same 

 kind of bodies are enveloped when they form a pellicle on the 

 surface of infusions, or adhere in a more or less globular shape. 

 On this subject the remarks of Dr. Arlidge, in the first part of 

 Pritchard's Infusoria, may be cited with advantage. He says, 

 " When we come to examine an infusion rich in these organisms, 

 numerous jelly-like colourless masses of different size and figure 

 may be met with on the walls of the vessel, and on the surface 

 of the fluid. These, when young, resemble small balls, from 

 1 — 1000" and less in diameter ; but as they continue constantly to 

 enlarge, they acquire a clustered outline, and exhibit themselves as 

 colourless masses, and films of very considerable superficial di- 

 mensions and thickness, resembling soft palmellae in consistence. 

 Like these, they are composed of a transparent mucus, in which 

 numberless punctate or linear corpuscles are embedded.-" Now, 

 if we could make the mucus more dense and tough, multiply 

 the " punctate or linear corpuscles " indefinitely, and introduce a 

 sprinkle of larger cells analogous to those of the yeast, we 

 should have a vinegar plant as its structure appears to me. 



The yeast plant is shown, as already stated, to be intimately 

 connected, if not identical with, several vegetable forms to 

 which distinct names have been assigned; but, both upon 

 botanical and chemico-physiological grounds, it would be very 

 interesting to ascertain to what extent that form of it known as 

 the vinegar plant is associated with bacterium bodies. It is not 

 enough that in one or two cases we find quantities of these 

 bodies present when alcohol or saccharine matter is converted 

 into vinegar — the question is, are they always present, and do 

 they seem to be the particular agents by which the vinegar- 

 making is carried on. To ascertain this, the vessels of various 

 sorts of vinegar works should be examined, and when the process 

 is conducted by suffering a certain fluid to trickle over twigs or 

 shavings, it should be ascertained whether bacterium bodies 

 appear in quantity together with, or as a component part of the 

 Mycoderma aceti, of which M. Pasteur speaks. 



Omitting those cases in which vinegar or acetic acid 

 results from purely chemical processes, such as the destructive 

 distillation of wood, or the influence of spongy platina, it 

 appears to be obtained by the action of vegetable ferments on 

 saccharine matter or alcohol, neither of which can be present in 

 excess without stopping the process. Certain other substances 

 in small quantities are also required to be present, or the 

 growth of the organic bodies cannot proceed. In Germany, 

 where alcohol is cheap, vinegar is made directly from it. Large 

 VOL. iv. — NO. iv. s 



