168 PROCEEDINGS OF THE SOCIETY. 



arid found that it had three great advantages. First, when a delicate 

 object had been prepared in spirit and was afterwards transferred to oil 

 of cloves it usually shrank back in a degree that was often detrimental : 

 Rhodium oil did not cause it to do this. Second, when a very delicate 

 object with small passages had been in oil of cloves it was often found 

 that the oil of cloves ran out quicker than the balsam ran in, resulting 

 in an appearance as if air had got into the tissues : this was avoided by 

 the use of Ehodium oil. Third, an object could be transferred direct 

 to this oil from water or dilute acetic acid without the necessity of 

 passing it through spirit. It gave as good results as oil of cloves, and 

 rendered mounting in the last named respect a somewhat less trouble- 

 some process. 



Mr. Karop inquired if Mr. Michael had tried it upon anything else 

 than insect preparations '? It seemed to him somewhat strange that an 

 essential oil should be miscible with water. 



Mr. Michael said he had tried it upon a few other objects, but had 

 not much histological work to try it upon at present. He found that it 

 did not produce any milkiness in objects transferred to it from water. 



Mr. Suffolk asked if it was easily procurable ? 



Mr. Michael said he thought it could be got at almost any chemist's, 

 especially such as supplied materials to perfumers ; but the finer 

 quality should be asked for. 



The President said he was not yet able to give any practical 

 account of the piece of apparatus which he held in his hand, but he 

 thought the Fellows present would be interested to know that it was the 

 first condenser made with the new German glass. It had a numerical 

 aperture of 1 • 4, working at the same distance as the achromatic conden- 

 ser also made by Messrs. Powell & Lealand, but this was also practically 

 apochromatic. He had not yet had the pleasure of trying it, but he 

 hoped to be able to do so in a very short time. 



Mr. T. B- Rosseter's paper " On the Generative Organs of Ostra- 

 coda " was read by Prof. Bell. 



Prof. Bell said, with regard to the question of motion in the sperma- 

 tozoa, he did not think that the observations were really out of agree- 

 ment with Prof. Huxley, who probably meant that there was no active 

 movement. Of course, if there were absolutely no movement, it was 

 tolerably certain that at no distant period the race would become extinct, 

 so that by the expression, " totally deprived of mobility," he supposed 

 was meant that they had not the same activity as that of the flagellate 

 forms. 



Mr. Michael thought it was a fact that no motion could be made out 

 in the case of several of the Arthropods. Mr. Campbell said in his 

 paper that he could not detect any motion in the spermatozoa of some of 

 the spiders, and he had himself found the same thing in the case of some 

 of the Acari. 



Prof. Bell thought that the only cases in which flagellate spermato- 

 zoa occurred were in the Scorpions and in Limulus. 



Prof. Stewart supposed it was rather a lapsus linguse on the part of 

 Prof. Bell when he said the flagellate spermatozoa were rare amongst 

 these classes, because amongst the insects they found them to be all — or 



