HISTORICAL ACCOUNT OF T^NIA CUCUMEPJNA. 667 



is usually found in the hinder part of the small intestine. Since it 

 possesses a great elasticity, and can be drawn out almost like a thread 

 to three or four times its usual length, the end of the chain is often 

 found in the neighbourhood of the large intestine, in the interior of 

 which the free proglottides, which are readily recognisable from their 

 red colour and elliptical form, are usually accumulated in great 

 numbers. 



Although this worm is quite as frequent in the cat as in the dog, 

 Linn4 has applied to it the name Tcenia canina, which has since been 

 changed more than once (by Pallas into T. moniliformis, and by Goze 

 into T. elliptica). Eudolphi and his followers, indeed, believed that 

 the worms found in the dog and in the cat should be distinguished as 

 two distinct species 1 (T. cucumerina and T. elliptica), and at the time 

 of the first edition of this work I was of the same opinion. But as 

 the result of renewed and careful investigation, I am now obliged to 

 agree with Goze, that it is impossible to discover any radical differ- 

 ences between them. 2 



If now it be asked on what grounds this T. elliptica is included 

 among human Helminths, we may answer, in the following way : 



Linne", who first recognised T. canina, as a specific form, and 

 rightly regarded the bilateral position of the sexual opening as its 

 most important character, also maintained that it was occasionally 

 found in man. 3 He even asserted that such cases were known to 

 him. But this assertion was gradually forgotten. Pallas contra- 

 dicted it, while Goze, Bloch, and Kudolphi did not deem it worthy of 

 mention. But, in spite of this, the worm deserves the place assigned 

 to it by Linne, 4 although it occurs in man only occasionally and ex- 

 ceptionally, and usually only during childhood. 



In the Museum of Comparative Anatomy, in Halle, there is, among 

 other Helminths, a preparation which, according to the label written 

 by H. Meckel, contains a convoluted T. canina, Linn., which was 

 voided by a boy called Krebs during his stay in the surgical wards 

 of Blasius. Through the kindness of Professor Welcker, I have 



1 Tcenia elliptica was also erroneously described as destitute of hooks. 



2 The fact that in the dog Tcenia cucumerina often attains a larger size can hardly be 

 considered as a specific difference, since the same is true of Ascaris lumbricoides and of A. 

 mystax, when they occur in different hosts. Even the statement of Krabbe ("Rech. 

 helminthol. ," p. 40). that in Iceland the cat is exempt from this Tcenia, while dogs fre- 

 quently suffer from it, does not seem to me to decide the matter. 



3 " Amoenit. acad.," ii., p.. 81. 



4 I now perceive that my statements in the first edition of this work (p. 402) regarding 

 a Tcenia cucumerina, which Eschricht had received as voided by a Moorish slave in St. 

 Thomas, are based upon an error, since the parasite was not T. cucumerina but T. cucur- 

 bitina ( = T. solium, Auct.) (See Nova Acta Acad. Cces. Leop.-Carol., Suppl. ii., t. xix., p. 

 139. 



