RUMINANTTA 341 



heretofore had not exhibited the slightest advance either in 

 respect of size or structure. 



At noon on the 28th I again sought for the larger larvae, 

 first of all on the slide covered with fine earth, and afterwards 

 within the remains of the upper half of the original earth-worm. 

 On the slide I could detect none, but within the intestine of 

 the worm there were still two living larvae left, whose characters 

 corresponded precisely with the largest that I had previously 

 obtained from the same source only the day before. They had 

 undergone, however, no further change in structure, and their 

 measurements remained precisely the same. 



At 12.30 p.m. I snipped off two or three of the terminal fern- 

 fronds on which I had placed a few advanced larvae. On 

 examination under the half-inch objective I immediately de- 

 tected one of the larvae cruising about most actively. On 

 adding a drop of water it soon rushed across the field of the 

 microscope, its movements being thoroughly eel-like. The size 

 of this larva had so much increased that it was now visible to 

 the naked eye, measuring, indeed, as much as ^" of an inch 

 from head to tail. Moreover, its organisation had advanced in 

 a marked degree. Thus, the digestive organs were better 

 defined, and on one side of them there appeared a regularly 

 arranged congeries of cellules, forming the commencement of 

 the reproductive organs. As yet, however, I could not pro- 

 nounce as to the sex. 



At 1.45 p.m. I again examined a few grains of earth from 

 the jar, when I at once noticed five or six active embryos whose 

 structure failed to show the slightest advance upon that origi- 

 nally described. It was evident that the jar contained thou- 

 sands of them ; and since no ova were found, it became pro- 

 bable that all their embryonic contents had escaped to swell the 

 number of free larvae, leaving their very delicate envelopes to 

 perish. I think I had hit upon the most suitable degree of 

 moisture favorable to this result. 



In the next place I sought for the earth-worm that had been 

 placed in the infested soil between two watch-glasses. It had 

 escaped. This obliged me to transfer the mould to a rather 

 wide-mouthed and open phial, in which four more fresh lumbrici 

 were placed. I feared the closing of the bottle would be 

 detrimental. 



Later in the day I selected an earth-worm which had not 

 been exposed to strongyle infection, but which was in a mori- 



