TRANSACTIONS OF SECTION D. 649 



contracted the disease and died, showing how easily the skin may be prepared for 

 the reception and invasion of the organism. 



The cold season (October to February) is more favourable to the growth of 

 the bacillus, as it has been shown to be destroyed at a moderate temperature 

 (37° C.) and on the other hand to grow profusely when placed for a week in a 

 freezing mixture of ice and salt. 



The experiments have also shown that fish akin to salmon are much more 

 susceptible to the disease than others, as rainbow trout, river trout, and sea trout 

 when attacked succumbed in from two to four days, while dace and gold-tish died 

 in about eighteen days and thirty-five days respectively. 



That dead fish, whether diseased or not, are a suitable medium for the growth 

 of the organism and propagation of the disease has been shown by the transmission 

 of the organism from diseased fish to healthy dead fish in the same water, and 

 also from the dead fish to the living, and I would strongly urge that all dead fish 

 and animal matter should, immediately it is observed, be removed from the river 

 and burned, not buried, as by burying the organism is left iu a condition to be 

 again carried into the stream. 



The chief characteristics of the bacillus are these : — 



A short thick bacillus with rounded ends and actively motile. 



Non-spore-bearing. 



Grows profusely at the room temperature. 



Grows profusely when exposed to 0° C. for a week. 



Shows little or no growth at 37° C. 



Is killed at 37° C. in about six days. 



Liquefies gelatine with extreme rapidity. 



Coagulates and digests milk. 



Grows well in sea-water. 



Forms a cloudiness in glucose agar in the neighbourhood of the growth, 



Strict aerobe. 



Involution forms, only observed on glucose media. 



Does not stain by Gram's method. 



Pathogenic to fish. 



Non-pathogenic to frogs, mice, and guinea-pigs. 



SATURDAY, SEPTEMBER 13. 



The Section did not meet. 



MONDAY, SEPTEMBER 15. 

 The following Papers were read : — 



1. The Segmentation and Early Developmental Stages of the Australian 

 Native Cat (Dasyurus). By Professor G. B. Howes, F.R.S. 



2, Recent Intercrossing Experiments with Dogs. 

 By Professor J. C. Ewart, F.R.S. 



3f Flower -like Insects from the Malay Peninsula, 

 By Nelson Annandale. 



