ASCAEIS LUMBltlCOIDES. 309 



of whicli, however, appeared to have escaped from the egg even 

 after a lapse of seven months in water. In the case of A. megalo- 

 cephala, I have reared quantities of free active embryos in a space 

 of less than five months, and I have also succeeded in rearing con- 

 siderable numbers of similar larv« from the eggs of Ascaris oscu- 

 lata, both in fresh and salt water.* Notwithstanding these limita- 

 tions, I am confident that the time is not far distant when we 

 shall be able to expose the whole chain of Ascaris-development, 

 which, at present, it must be admitted, is totally disconnected by 

 several missing links. 



Practical Considerations. — As a general rule, it may be con- 

 fidently stated that the presence of one or two Ascarides in the hu- 

 man intestinal canal is not attended with any marked constitutional 

 disturbance ; but, every now and then, instances turn up where the 

 reverse of this happens, whilst, in some few cases, their presence 

 is accompanied with the gravest consequences to the unfortunate 

 " bearer." Usually, only a sohtary specimen or, at most, from three 

 to six or eight of these worms are found in the same person at one 

 time, but, occasionally, their numbers are considerable. Thus, 

 Kiichenmeister alludes to a case where one hundred and three 

 examples were passed by a child, and he also quotes an instance 

 where the intestinal canal of another child harboured between 

 three hundred and four hundred of these worms ; but a still more 

 remarkable case is recorded by Gilli (in the " Turin Journal of the 

 Medical Sciences"), where no less than five hundred and ten were 

 passed by a child. But few cases are on record where any consi- 

 derable number of Ascarides have infested the intestinal canal of an 

 adult ; but, as the above instances sufficiently testify, large num- 

 bers occur in children, in whom, also, they are particularly frequent. 

 The proper habitat of Ascaris lumbricoides is the small intestine, 

 but it is not unfrequently found in the stomach, and other parts of 

 the digestive canal. From these localities it sometimes migrates, 



* Details respecting the production of these nematode larvas by experiment will, I 

 trust, hereafter be found in the " Eeports of the British Association" for 1864. 



