264 Medicine, [Chap. IV. 



cularly his account of the composition of the red 

 globules of the blood, and of animalcula observed in 

 the semen) are now discredited, it must still be ad» 

 mitted that he advanced many steps in bringing to 

 light the more minute parts of the animal structure. 

 Nuck likewise soon afterwards added to the stock of 

 knowledge by his injections of the lymphatic glands. 

 I'he anatomical plates of Bidloo and Cowper, pub- 

 lished about this time, are also entitled to respectful 

 notice. 



li\ the latter part of the seventeenth century 

 anatomy was greatly advanced by the invention of 

 injections, and the method of making what are 

 commonly called preparations. These two modern 

 artg have been. of great advantage in this science: 

 they have introduced not only an unexpected degree 

 of correctness, but an elegance in demonstrations 

 which formerly could not have been supposed to be 

 possible. Tliey began in Holland under Swammer- 

 dam and Ruysch, and were afterwards employed in 

 England by Cowper, St. Andre, and others. Ruysch 

 possessed a singular excellence in injections, which 

 has been supposed by many not to have been equal- 

 ed since, and which certainly has not been surpass- 

 ed. The anatomists of former ages had no other 

 knowledge of the blood-vessels than such as they 

 were able to obtain by laborious dissections, and 

 by pursuing the smaller branches of them, upon 

 favourable occasions, when they happened to be 

 more than commonly loaded with red blood : but 

 filling the vascular system with a bright-coloured 

 wax presents a distinct view of the large vessels, ren- 

 ders tlie smaller much more conspicuous, and makes 

 thousands of the very minute ones visible, which. 



