178 HETEKOGENETIC ORIGIN OP 



shown in A, and a more advanced stage in B. In all other respects 

 the apples were perfectly sound and of a delicious flavour, and 

 none of those eaten anterior to the date mentioned showed any 

 unusual appearance. Towards the end of December the above 

 photographs were taken ; and on consulting Lindley's " Vegetable 

 Kingdom," it became plain, from a figure there shown (p. 559), that 

 these points of change occurred at the junction of the ovarian and 

 calycine portions of the fruit. 



I examined portions of the altered tissue under the microscope, 

 fully expecting to find some Mould as the cause of the change. 

 But, much to my surprise, after a tolerably careful examination, I was 

 unable to feel sure that organisms of any kind were to be found in 

 the tissue which had become thus altered. Subsequently I tried to 

 stain some sections, and made a still more careful examination, with 

 the result that I found on, or in, the primordial utricle of many 

 cells, cocci-like bodies looking like the germs of microorganisms. 

 But as their nature seemed doubtful I took two of the apples to Dr. 

 Allan Macfadyen and asked him kindly to see whether any microor- 

 ganisms could be developed from this altered tissue of the apple. 

 On January sth he wrote to me, as follows : " I was unable to 

 detect the presence of Bacteria in the Canadian apples you left 

 here, by microscopical examination. I accordingly made a number 

 of subcultures, but in no instance have I succeeded in obtaining a 

 growth." ' 



I had by this time only three of the apples left, so I placed them 

 in the incubator at a temperature ef 76° F. and there left them for 

 eight days. On section two of them were found to present the 

 brown discolouration in the usual situations to a well-marked 

 extent. Some portions of the brown tissue were broken up with 

 needles, placed in a dilute solution of the mastzellen stain, and 

 were afterwards submitted to careful examination with the micro- 

 scope. Thei-e was certainly a very distinct increase of the 

 cocci-like bodies in the primordial utricle, remaining unstained, as 

 in Fig. 9, C ( X 700), though all the other granules in the cells had 

 become strongly stained. In some places the cocci were seen in 

 distinct rows, branching and crossing one another as in J ( x 375), 



» Some time previously Dr. Nabarro, of University College, had been similarly 

 unsuccessful in obtaining growths from a potato which had been treated in the 

 manner I have detailed on p. 173, and in which organisms seemed to be present 

 at an early stage. Such lack of success after trials with a few culture media is, of 

 course, far from disproving the presence of microorganisms. 



