92 



SMUT IN WHEAT. 



Bt T. Stephens, M.A., P.a.S. 



The letter of Mr. Joseph Barwick, read at the last meeting 

 of the Eoyal Society, is specially interesting as showing a 

 spirit of intelligent enquiry, and a desire to work out the 

 solution of one of the numerous problems connected with 

 natural phenomena, which are to some extent a matter of 

 uncertainty even to those who have devoted their lives to 

 scientific research. Mr. Barwick's long experience as a practical 

 farmer, and the results of his special experiments, have shown 

 him that the origin and spread of the parasitic disease to 

 which he refers is involved in much obscurity. He has, 

 however, perhaps not sufiiciently realised that a thorough 

 knowledge of the general history of these low forms of 

 vegetable life must be acquired before one can be 

 sure of a satisfactory basis for experiments. The absence 

 here of facilities of access to standard works and recent 

 reports increases the difficulty of investigation, but the main 

 facts of the propogation of the disease in question are 

 sufficiently well-known for all practical purposes. Smut 

 and bunt may be regarded as convertible terms. Though 

 they are spoken of as distinct species by some authorities, I 

 can say from j)ersonal knowledge that what is called smut in 

 Tasmania bears the same name in some parts of England, 

 while elsewhere it is known as bunt. It is a minute fungus 

 belonging to the family Coniomycetes, sub-order TJstilaginei, 

 and has been described at different times under various names, 

 as Uredo caries, TJredo foetida, Tilletia caries, and Ustilago 

 segetum ; but it is pretty well-known now that the form in 

 which the disease is always recognised is simply one of 

 the conditions or stages in the life of a fungoid plant, which 

 in other stages is known by a different name. In the case of 

 animal parasites, such as the sheep fluke (Fasciola hepatica), 

 the stage in which it appears to the Ordinary observer is 

 only the final development in the sheep of a cycle of changes, 

 one of which, at least, cannot take place except in the body of 

 an animal belonging to a totally different class. Again, the 

 disease in sheep called " sturdy " or " staggers " — the common 

 term in Tasmania is a " cranky " sheep " — is derived from the 

 ova of the tape worm {Taenia) in a dog which, voided on the 

 grass, are taken up by the sheep with its natural food, and 

 find their way through the circulation into the brain, and 

 are there developed into a new form called Ccenums cerehratis, 

 which, lodged near the inner surface of the skull and pressing 

 on the brain, produces the symptoms which are well-known 

 to most sheep farmers. So the blight known as " corn 

 mildew " (Puceinia graminis) has been definitely cerrected 



