320 NERVOUS SYSTEM. 



tions of the cerebrum, to the laminated surface of the cerebel- 

 lum, and the cineritious part of the Spinal Marrow. 



4. The articulated tubes present patulous ends to this granu- 

 lated collection, which ends are fitted for the purpose of re- 

 ceiving them directly, and for the distillation of the Nervous 

 fluid, (Liquor Nervosus.) 



5. The cylindrical tubes of the motiferous nerves are imme- 

 diate continuations of the nodulated tubes. This is perceptible 

 in the nerves of the medulla spinalis and of the cerebrum, ex- 

 cepting the Olfactory, the Optic, and the Auditory Nerves, which 

 are unchanged nodulated tubes. 



6. Professor Ehrenberg's observations on living nerves have 

 not yet exhibited the circulation of a nervous fluid in them, but 

 he declares neither for nor against it. 



7. The Ganglions, or Nervous knots, consist of the articulated 

 tubes alone, or mixed with the cylindrical tubes. They have 

 also a very fine network of blood-vessels, with nervous gra- 

 nules intermixed with them. They are, in fact, comparable to 

 brains. 



In the present state of microscopical anatomy it is impossi- 

 ble to tell whether the foregoing is a history of delusions or a 

 narrative of fact. Every improvement of the microscope, 

 since its first discovery, has, in subverting preceding opinions, 

 claimed for itself infallibility; yet there has been, at no period, 

 uniformity in ihe results of experienced observers. We have, 

 in the present instance, according to Ehrenberg, Professors 

 Muller and Wagner approving and confirming by their testi- 

 mony; and Professors Remack, Treviranus,* Krause, and Volk- 

 rnan, objecting. Such an instrument as a highly magnifying 

 microscope, in establishing new relations of vision, leaves us 

 destitute of those countertests which are indispensable to infal- 

 libility; its indications may be right, but they always present 

 much room for doubt. 



* Progress of the Anatomy and Physiology of the Nervous System, during 

 the year 1836, by Professor Muller, of Berlin, (copied into Essays on Physiology 

 and Hygiene, Phila. 1838,) who does not himself seem to be an ardent convert to 

 the views of Professor Ehrenberg; as he says, "Whether or not the minute ele- 

 mentary structure of the nerves is known, must still remain a matter of doubt," 



