ENTOZOA. 



115 



Dr. Arthur Farre, whose powers of patient 

 and minute observation and practised skill 

 with the microscope, are well known to those 

 who have the pleasure of his acquaintance, 

 discovered, by theexamination of recent Trichinae 

 under favourable circumstances, that they pos- 

 sess an intestinal canal with distinct parietes. 

 He describes it as commencing at the large end 

 of the worm, bounded by two parallel but 

 slightly irregular lines for about one-fifth of 

 the length of the body, and then assuming a 

 sacculated structure which " becomes gradually 

 lost towards the smaller end where the canal 

 assumes a zig-zag or perhaps spiral course, and 

 at length terminates at the small end."* 



In a recent examination of some Trichina 

 from an aged male subject at St. Bartholomew's 

 Hospital, I perceived a transverse slit close to 

 the small extremity on the concave side, which 

 I regard as the anus. 



The muscles which are affected by the Tri- 

 china are those of the voluntary class ; and the 

 superficial ones are found to contain them in 

 greater numbers than those which are deep- 

 seated; the pectoralis major, latissimus dorsi, 

 and other large flat muscles usually present 

 them in great abundance. They have been 

 detected in the muscles of the eye, and even 

 in those belonging to the ossicles of the ear, 

 and of whose actions we are wholly uncon- 

 scious: they also occur in the diaphragm, in 

 the muscles of the tongue, in those of the 

 soft palate, in the constrictors of the pharynx, 

 in the levator ani, in the external sphincter ani, 

 and in the muscles of the urethra. But they 

 have not yet been detected in the muscular 

 tunic of the stomach and intestines-, in the 

 detrusor urinae, or in the heart. It is an inte- 

 resting fact that all the muscles infested by the 

 Trichina are characterized by the striated ap- 

 pearance of the ultimate fasciculi : while the 

 muscles of organic life, in which they are 

 absent, have, with the exception of the heart, 

 smooth fibres, not grouped into fasciculi, but 

 rcticularly united. 



From the instances of this parasitical affec- 

 tion of the human body which have already 

 been recorded, and from other unpublished 

 cases in which I have examined the worms, 

 it is evident that their presence in the system 

 is unconnected with age, sex, or any particular 

 form of disease. They have been found in the 

 bodies of persons who have died of cancer of 

 the penis ; tubercles in the lungs ; exhaustion 

 of the vital powers by extensive external ul- 

 ceration of the leg ; fever combined with tu- 

 bercles in the lungs; aneurism of the aorta; 

 sudden depression of the vital powers after a 

 comminuted fracture of the humerus ; diar- 

 rhea. 



The cases which had occurred before the 

 publication of the first description of this 

 Entozoon led me to conceive that, although the 

 species was of so minute a size, yet the num- 

 ber of individuals infesting the body was so 

 immense, and their distribution through the 

 muscular system so extensive, that they might 



* See Medical Gazette, December, 1835. 



occasion debility from the quantity of nutri- 

 ment required for their support; and I ob- 

 served " that it was satisfactory to believe, that 

 the Trichina are productive of no other con- 

 sequences than debility of the muscular system; 

 and it may be questioned how far they can be 

 considered as a primary cause of debility, since 

 an enfeebled state of the vital powers is the 

 probable condition under which they are 

 originally developed. No painful or incon- 

 venient symptoms were present in any of the 

 above-mentioned cases to lead the medical 

 attendants to suspect the condition of the mus- 

 cular system, which dissection afterwards dis- 

 closed : and it is probable that in all cases the 

 patient himself will be unconscious of the 

 presence of the microscopic parasites which 

 are enjoying their vitality at his expense."* 

 Since writing the above, a case has occurred 

 in which the Trichinae were met with in the 

 muscles of a man who was killed while in the 

 apparent enjoyment of robust health by a frac- 

 ture of the skull. I received portions of the 

 muscles of the larynx of this individual from 

 my friend Mr. Curling, Assistant-Surgeon to 

 the London-Hospital, who has recorded the 

 case in the Medical Gazette, and the worms 

 were similar in every respect to those occurring 

 in the diseased subjects. The deduction there- 

 fore of the development of the Trichina being 

 dependent on an enfeeblement of the vital 

 powers is invalidated by this interesting ex- 

 ample .f 



Leaving now the consideration of Entozoa, 

 which from their minute size and organization 

 would have ranked with the vast assemblage 

 of animalcules which are collected under the 

 head Infusoria in the Regne Animal, we come 

 next to the consideration of the animals which 

 form that scarcely less heterogeneous class, the 

 Entozoa of Rudolphi. These are distributed by 

 that Naturalist into five orders, which may be 

 synthetically arranged and characterized as 

 follows. 



ORDO I. CYSTICA, Rud. (KVO-TH;, vesica.) 

 Vermes vesiculares, Blasenwiirmer, 



Cyst-worms or Hydatids. 

 Char. Body flattened or rounded, conti- 

 nued posteriorly into a cyst, which is 

 sometimes common to many indivi- 

 duals. Head provided with pits (bo- 

 thria two or four) or suctorious pores 

 (four), and with a circle of booklets 

 or with four unarmed or uncinated 

 tentacles. No discernible organs of 

 generation. 



06s. This order is not a very natural one ; 

 the species composing it are closely allied to the 

 Tape-worms in the structure of the head, and 

 when this is combined with a jointed structure 

 of the body, as in the Cysticercus fasciolaris 

 common in the liver of Rats, the small caudal 

 vesicle forms but a slight ground for a distinc- 

 tion of ordinal importance. The Cystica of 

 Rudolphi form part of the Order Tanioidea of 

 Cuvier ; and may be regarded as representing 



* Zoological Transactions, vol. i. p. 315. 

 t Zool. Trans, vol. i. p. 323. 



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