Cervelat is a sausage made from pork and usually seasoned with garlic. Land jaeger is a Swiss version - a black, wrinkly and heavily smoked sausage. The German cervelat is goettinger and is made with spiced beef and pork. The English version is saveloy and contains saltpetre, which gives it a reddish tinge.
Dowell, P., Bailey, A. (1980) The Book of Ingredients, Dorling Kindersley. ISBN 0718119150.