3 INTRODUCTORY CHAPTER, 
There is no agreement amongst jurists on the subject 
of retaliation, except on the principle that it is an 
exceptional measure and one to be used oniy as a last 
resort. The means adopted by Great Britain and France 
for retaliation against the Central Powers were based on 
the principles of blockade, but with considerable 
extensions of the rules formerly adopted. It did not 
lie within the province which Dr. Colombos has defined 
to discuss the future of the Law of Blockade in detail, 
or to examine the contention advanced by the British 
Foreign Office in their correspondence with the United 
States that the measures taken under the Orders in 
Council were a legitimate development of the Law of 
Blockade under the modern conditions of naval warfare. 
He points out, however, that close blockades of the old 
type had become impracticable, and long-range blockades 
must now be accepted. 
One of the most important of the subjects of the 
decisions in the Prize Courts was that of Contraband.® 
No subject, as Dr. Colombos points out, has aroused so 
much discussion and controversy, and experience proved 
the futility of the attempt made by the Declaration of 
London to classify various articles under the headings 
of absolute and conditional contraband and goods which 
were not to be so treated. Further, the application of 
the doctrine of Continuous Voyage or Ultimate Destina- 
tion to Absolute Contraband only (except in cases of 
countries without a seaboard) laid down in the Declara- 
tion of London was illogical and failed. It has been 
sald that the distinction between absolute and conditional 
contraband goods is more specious than real, and this 
proved to be the case under the conditions prevailing 
5 See post, Chap. V. 
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