H. T. WHITTELL ON THE DEGENERATION OF HYDATID CYSTS. 51 



appearances as the larger specimens. Dilute acetic acid does not 

 appear to affect them, nor do they polarize light. I have been 

 unable, with the highest powers in my possession, to make out any 

 internal structure. In some instances I have found a number of 

 smaller ones apparently attached to each other, and so forming one 

 large specimen, but I have not discovered anything like a cell wall, 

 and I have not been able to satisfy myself whether this appearance 

 is due simply to a mechanical or accidental aggregation of the bodies 

 to each other, or to some phase in their life-history. 



Having been practising in Australia for the greater part of my 

 life, I had had no opportunity of seeing the parasites which some 

 observers had supposed to be the cause of the cattle plague, but I 

 tliought I could detect some degree of resemblance between the 

 bodies under my microscope and drawings of these parasites that 

 had been sent out to us. We were, however, anxious to obtain 

 an authoritative opinion, and it was arranged that I should send one 

 or two slides to Dr. Cobbold, and ask him his opinion respecting 

 them. In reply, Dr. Cobbold wrote, " I regard the peculiar organ- 

 isms contained in the slides you have transmitted as psorospermial 

 bodies of the nature of pseudo navicellae. They are not precisely 

 like any I have myself hitherto encountered, and they differ still 

 more from those described by foreign writers. The general facts 

 recorded by you remind me forcibly of the case reported by Gubler 

 in 1858, in which there were twenty cysts in the liver ; the largest 

 of which (six inches in diameter) was, during life, diagnosed as an 

 Hydatid. Reference to this and other cases are given in my paper, 

 * On the Nature of Pseudentozoa found in Diseased and Healthy 

 Cattle,' originally published in The Lancet, for Jan. 27th, 1868. 

 It has been reprinted in the supplement to my ' General Treatise on 

 the Entozoa,' and in Prof. Gamgee's work on the Cattle Plague. 

 The whole subject of the gregariniform productions requires revision, 

 and it needs only a perusal of my short paper to show how intricate 

 and involved are the facts hitherto described. Practically it is im- 

 portant to remember that all liver cysts are not necessarily due to 

 Hydatids, since Virchow, Gubler, Dressier and others, have en- 

 countered cystic formations of the pseudentozoal character above 

 described." 



I found on one of the slides, mounted with some of the fluid I 

 have just referred to, a solitary, filiform, worm-like body, which I 

 would gladly have sent on to Dr. Cobbold, but as it was an acci- 

 dental find on a slide not prepared for the cabinet, I feared that no 



