TEE AGRICULTURAL JOURNAL. 



747 



One part of phosphoric oxide equals 

 2.183 parts of tri-calcic phosphate. 



One part of mono-calcic phosphate 

 equals .t)07 parts of phosphoric oxide. 



One part of di-calcic phosphate equals 

 .522 parts of phosphoric oxide. 



One part of tri-calcic phosphate equals 

 .458 parts of phosphoric oxide. 



Questions. 



1. Explain what superphosphate is, and 

 how it is made. 



2. What sort of soils is superphosphate 

 best suited for, and why does it act so 

 quickly ? 



3. What is the action of lime on super- 

 phosphate ? 



4. What is the object of mixing super- 

 phosphate with bone-dust ? 



5. Mention a crop for which phosphates 

 are a prime necessity. 



6. if a sample of bone-dust contains 20 

 per cent, of phosphoric oxide, how much 

 tri-calcic phosphate will it have ? 



7. What is basic slag ? Why is it so 

 good for sour soils ? 



8. Explain exactly what is meant by 

 soluble phosphate in an analysis. If a 

 special manure is said to contain 25 per 

 cent, of soluble phosphate and 5 per cent, 

 insoluble phosphate, calculate the amount 

 of phosphoric oxide in each. (Answer : 

 11.45 per cent, soluble, and 2.29 per cent, 

 insoluble phosphoric oxide.) 



Rinderpestm 



BILE INFECTION. 



rrHE following letter appeared in the 

 i " Natal Witness." It is in reply to 

 an article by Mr. Pitchford, in No. 20, 

 Vol. IV., and reproduced by the above 

 journal : — 



Sir, — In your edition of December 

 llth an interesting article on rinderpest 

 is published, written by Mr. Watkins- 

 Pitchford, in which, in discussing the 

 possibilities of communicating rinderpest 

 by the inoculation of rinderpest bile, the 

 following sentence occurs : — 



"Although later the same authority 

 (Turner) is reported {perhaps incorrectly) 

 as admitting that the question whether 

 the gall can cause the disease is still an 

 open one." 



This is certainly incorrect"; the question 

 as far as I am concerned, has never been 

 doubtful. If there is one fact which is 

 well established with regard to rinderpest 

 it is that rinderpest gall does not /;e,r se, 

 usually, or even frequently, convey rin- 

 derpest. I should say that it never does 

 so, only I do not like to make an absolute 

 statement with regard to a matter of this 

 nature. Certainly I have never met with 

 such an occurrence, and have never 

 heard of rinderpest being spread by gall 

 where there was any reasonable certainty 



that the animals were not previously in- 

 fected. I held this opinion in 1897, and 

 my experience during 1901 has only 

 made me still more convinced of the 

 truth. 



I do not say that rinderpest has never 

 followed bile inoculation, for this has fre- 

 quently occurred. Sometimes the disease 

 has been directly caused by the bile in- 

 oculation. Not by the insertion of the 

 gall, but by want of care and cleanliness 

 in the operator. Koch recommended that 

 the inoculation should be made from the 

 clean area towards the infected centre, 

 because he was aware that the gall was 

 not only curative, but that until the tenth 

 day it was not preventative. If a series 

 of animals are all infected with gall, and 

 then rinderpest blood is administered to 

 one animal of the series daily until the 

 whole have been inoculated, it will be 

 found that while, in exceptional cases, 

 where the bile is inert, all may have the 

 disease, that those inoculated with blood 

 up to the sixth day after the injection of 

 bile will certainly suffer ; that those in- 

 fected on the eighth day may have the 

 rinderpest, but that usually those tested 

 on the eighth and tenth days escape. 



This being the case, any one animal in 

 the herd which has been infected will 



