366 Investigation of Rotting of Oranges 



When the oranges reached England their condition was as follows: 



How packed 

 Packed in sawdust and thin paper 

 Packed in tinfoil . . 

 Ordinary tissue paper 

 Steamed and WTapped in tissue paper 

 In dried banana leaves . . 

 Packed without wrapping of any kind 



From the above table it would indicate that the best series were 

 those isolated by thin paper and dry sawdust and the worst those 

 subjected to heat and moisture. 



One noticeable feature about the unwrapped oranges was that 

 wherever a diseased orange occurred a large excess of moisture occurred 

 in the same area. This suggested a line of enquiry as to whether 

 moisture might not help in the spread of the disease. 



The sound oranges were used for inoculation experiments and the 

 preparation of culture media. 



Two fungi were found on the bad oranges; one was the common 

 fungus Penicillium italicum, while the other had short colourless hyphae 

 with small black zygospores and appeared to be one of the Mucorineae. 

 It was found impossible to isolate the latter but the former was easily 

 isolated and cultivated on a 3 per cent, gelatine medium mixed with 

 orange juice. This orange juice gelatine was used throughout, sterihsed 

 in the autoclave. The pure cultures obtained were used for infecting 

 sound oranges, in some cases spores only being used, in others mycelium, 

 and in others mycelium together with a little culture medium. During 

 the time that cultures were being obtained the skin of the orange 

 was investigated and the various tissues met with tested as regards 

 their chemical composition. Externally a fairly thick cuticle occurs, 

 below which is a single layer of cells with cellulose walls forming a very 

 shallow epidermis, and beneath this a many-layered tissue with cellulose 

 walls and variable size of cells forming a many-layered parenchyma, 

 often filled with small granular cell contents and yellow in colour. 

 Embedded in this yellowish tissue are many oil glands which extend 

 in many instances quite up to the epidermis and buried deep in the 

 tissue at the other, the glands being more or less oval in shape and 

 lined with a single layer of epithelium. 



Below this glandular layer another many-layered parenchyma 

 occurs with irregular shaped cells with large intercellular spaces and 



