The Microscope. 103 



the investigator, Mr. Stedman, has worked. The value of the work as 

 independent, skillful investigation, is not in the least particular to 

 be detracted fi-om by the following : 



While searching over past files of the Transactions of the Linnean 

 Society, vol. II., 1794, I happened upon an article entitled "Observa- 

 tions upon the Structure and Oeconomy of those Intestinal Worms 

 called Taeniae," by Mr. Anthony Carlisle, F. L. S., and read Nov. 

 6, 1792. Curiously enough, as will be seen by the extracts, the 

 author presents the same methods and elucidates the same fact 

 regarding the valves. ■ , 



These two papers, written nearly a century apart, afford us much 

 instruction as to the advance in technical detail lately arrived at. 

 From the earlier paper we learn that "a powerful magnifying 

 glass" revealed to him, the writer, no smaller elements than the 

 so-called "globular bodies," which from inference I take to be those 

 spots, which are called tests, and are so plainly seen with a loup. 

 As might be expected, Mr. Carlisle failed in his deductions just 

 where his microscope allowed him to speculate on the problematic 

 functions of the different parts. Beyond mentioning the preserva- 

 tion of the Taeniae in "fine si^irits," he gives no other methods than 

 those contained in the quotations. The species experimented upon 

 was Taenia Solum L., and, among other observations, he writes: 



I have often injected three feet in length of these canals with 

 coloured size, by a single push with a small syringe. The injection 

 will not, however, pass from below upwards along these canals. I 

 could never make it go in this direction beyond two joints, and it 

 appeared to be stopped by valves in the lateral canals, situated 

 immediately below the places where the cross canals are sent off, 

 The alimentary canal, as it is here described, is continued into the 

 extreme joint, where it becomes impervious, there being no opening 

 analogous to an anus. The individual joints have each a vascular 

 structure occupying the middle part which is composed of a 

 canal passing from the top of the joint to the bottom, and from its 

 sides. are ^ent off a number of lateral canals nearly at right angles ; 

 these vessels contain a fluid like milk, which is also globular, and after 

 the death of the animal it is found coagulated. When injecting this 

 middle vascular structure, I have often made the injection pass into 

 the alimentary canals, by a number of very small openings, but could 

 never, on the contrary, inject the central vessels from the alimentary 

 canals ; it would seem as if there were a valvular apparatus fixed at 

 the outer extremities of those radiated canals. The remaining part 



