26 A New Point of Resemblance in the 



destroyed, no blue colour being produced by guaiacum alone 

 or on the addition of peroxide of hydrogen. It is known 

 that other substances contained in the animal economy, and 

 belonging to the protein group, such as fibrin, myosin, 

 globulin, act like haemoglobin in the way of carriers of 

 ozone. I conclude, therefore, from analogy, as well as from 

 its properties above described, that in fresh vegetable sub- 

 stances there is contained an ingredient, probably albumin- 

 ous, which acts as an ozone-transferrer, and may be presumed 

 to be the agent with which oxygen enters into loose com- 

 bination. It certainly is not chlorophyll, which has been 

 compared with haemoglobin (by Baeyer in his paper referred 

 tO' above) on account of the property which they possess in 

 common of combining with CO. The difference in function, 

 however, is well marked, chlorophyll causing the elimination 

 of oxygen, while haemoglobin enters into combination with 

 it. In addition, the substance whose nature I am consider- 

 ing exists abundantly in the interior portions of fruits and 

 in many other structures, such as the potato, turnip, &;c., 

 which never contain chlorophyll. I think it probable 

 that considerable difficulty will be found in isolating 

 this substance, both on account of its destructibility and 

 because it is almost uniformly diffused through fresh 

 vegetable structures. It is probably intimately asso- 

 ciated with the vascular - tissue, since I have found that the 

 ozonic reaction, as well as the ozone-transferring function, 

 in fruits are most marked and persistent near the core, 

 where the vessels from the stalk are more abundant than in 

 the outer, more purely cellular, parts. A perhaps more 

 doubtful opinion is that this substance is attached to the 

 small cells or granules, called by Sachs " aleurone grains," 

 which, according to him, are mainly proteinaceous. They 

 resemble somewhat in size the red blood corpuscles, and I 

 have sometimes thought that minute sections of fruits, which 

 had been rendered blue by guaiacum, when examined under 

 the microscope showed the most intense colouration at the 

 spots where these aleurone grains occurred in groups. 



Whether what I have ventured to advance by way of 

 opinion prove to be correct or not, the following points have, 

 I think, been established : — (1) That the oxygen inhaled by 

 plants as well as by animals enters first into some form of 

 loose combination whereby it is ozonized or rendered active ; 

 and (2) that plants contain a substance, other than chloro- 

 phyll, having some important points of analogy with the 



