225 



exactly over the indiarnbber band, there would be no difficulty in using 

 thin glass for the cover. 



Dr. T. Spencer Cobbold, who had been announced to read a paper " On 

 Filarice in relation to the Febrile State,'' by Dr. Manson, explained that he 

 had been obliged to withdraw it for the present, and would therefore offer 

 some few observations upon a nicely mounted specimen of Strongijlus 

 filaria from the lung of a sheep This had been given to him by Mr. Cm'ties, 

 who had received it from Mr. Beaulah, by whom it had been prepared. The 

 slide, when placed under the microscope, showed very clearly many thou- 

 sands of larvae in the oviducts of the w^orm. The presence of these parasites 

 gave rise to what was known as the " husk " in sheep, and Str. micrurus 

 caused the same disease in cattle. Another species {Strongylus ^paradoxus) 

 was also found in the lungs of the pig. The specific differences between the 

 various species of the genus were readily determined by the shape of the 

 tail ol." the male, and in this matter we were much indebted to the labours 

 of Dr. Schneider. [Diagrams in illustration were exhibited]. Being very 

 desirous some time ago of tracing the development of these worms so as to 

 be able to find out some means of destroying them, or of preventino- their 

 ravages, he made a series of experiments upon Strongylus micrurus from 

 the lung of a calf. Knowing that many of this class of worms were 

 developed in mud, he placed a quantity of the ova in some mud in a watch- 

 glass, which was again placed in a fern case. On one occasion, whilst ex- 

 amining the contents of this glass, he was surprised to observe a sudden 

 upheaval of the surface of the mud, and found that it was due to a small 

 earth worm having crept into the watch-glass. It occurred to him at once 

 to examine the worm, and after carefully washing it, he dissected it, and 

 found the intestines to contain a very large number of embryos from the 

 watch-glats. He thought, therefore, that it was quite likely that the earth 

 worm might prove to be the " intermediate host," and all his subsequent 

 experiments had tended to confirm this idea. Endeavouring as far as 

 possible to imitate the natural conditions under which the further develop- 

 ment of these w^orms would be likely to be carried on, he placed some of the 

 embryos from the earth worm in some of the dew drops on a particular fern 

 in the case, and in two days he had the satisfaction of finding in these dew 

 drops two or three embryos of gigantic proportions. A few days after this 

 he obtained some more specimens from the same place, including some 

 young males, one of which was changing its skin. One remarkable differ- 

 ence between those in the mud and those in the dew drops was the very 

 greatly increased activity in .the last named, so active in fact that it was 

 necessary to compress them almost to danger of crushing them, in order to 

 keep them within the field of view. From these observations he came to 

 the further conclusion that in nature the larvae were to be found in the dew 

 upon the grass, with which they were taken up by grazing cattle. He did 

 not think, however, that they passed down into the stomach with the fodderj 

 but that their activity was such that they wriggled out of the contents of 

 the mouth, and got into the trachea in a direct manner. Here he had little 

 doubt their development would be completed in two or three days. He was 

 further confirmed in this opinion by placing some of the embryos from the 



