68 PARASITES OF MAN 



tion were Mr Schulze's heating table, the neutral tincture of 

 carmine, the tincture of hgematoxylon, and breeding experiments. 



" My method is founded essentially 



"(a) On the fact that the Cysticercus when it is fresh and is 

 stretched and conveniently prepared in pure water, or in chloride 

 of soda very much diluted, and afterwards brought gradually 

 from the temperature of the ambient air to that of the body of 

 higher animals and to degrees of heat still more elevated, until 

 life is extinct, keeps moving to and fro with more or less 

 energy throughout its body, using especially its suckers and 

 proboscis. 



" (b) On the greater imbibing power of the dead tissue 

 generally, which is undoubtedly far more apparent in insects 

 and plathelminths. 



" (c) On the experiments made to ascertain the value of the 

 two above- stated facts. 



"If, after having prepared a Cysticercus , newly extracted 

 from a pig in the way we have pointed out, we examine it with 

 a microscope on M. Schulze's heating table, we find that 

 usually it begins to move after 30 or 35 C., and each moment 

 with greater activity, especially after 38, 40, 42, 44, 45 C. 

 The temperature being raised progressively, we see that the 

 Cysticercus cellulose puts a stop to its movements occasionally 

 at 4546 C., seldom at 47 C., more frequently at 48 C., 

 sometimes at 49 C. ; and, in fifty and more experiments, only 

 one Cysticercus was able to live on beyond 49 C., standing still 

 at 50 C. 



" As soon as it stands still the parasite is dead. In fact, if 

 we lower again the temperature gradually to that of the ambient 

 air, and if afterwards we raise it a second time, we pass through 

 all the intermediate temperatures without the Cysticercus show- 

 ing the least signs of life. 



" But a more convincing proof of the death of the parasite is 

 got from the greater imbibing power of the tissue when life is 

 extinct, the same over the whole body of the plathelminths, and 

 their larval forms. If we dip the Cysticercus alive with its 

 head stretched in the neutral tincture of carmine or hsematoxylon 

 we can leave it there even two, four, eight, ten, or twelve hours 

 and more, without the head coloring or a real imbibition taking 

 place ; this begins only after the Cysticercus is dead, so that if 

 the Cysticercus is brought first to a temperature hot enough to 

 kill it (with M. Schulze's tables to one of 48, 49, 50 C.) and 



