6l8 PHILOSOPHICAL TRANSACTIONS. [aNNO IJOQ. 



as in the hemp-seed And the experiment of wheat infused in boiling hot 

 water does not always succeed. He likewise found salts not unlike those of the 

 hemp-seed, in infusions of a variety of pulse and grain from the East-Indies, 

 such as lupines, kidney-beans, vetches, millet, Guinea corn, and the sesamum 

 or oily grain: but the last yielded a much larger quantity of salt, and in a shorter 

 time than any of the rest. The salts of these different substances were also not 

 dissolvable on applying clean water to them ; but by letting the infusions con- 

 tinue to putrefy some weeks longer, they by degrees assumed irregular shapes, 

 and disappeared. He concludes then with this query, Are not these the oily 

 parts of the vegetables, which float in the scum, on the surface of the infusion, 

 crystallized? 



Explanation of the Figures of Plate 18. 

 These 5 different kinds of animalia infusoria belonging to the genus of volvox 

 of Linnaeus, are here represented both in their perfect and in their divided state. 



Fig. 1 represents the volvox ovalis, or egg-shaped volvox: at c and b it is expressed in its natural 

 shape: at a the manner in which it becomes two animals, by separating across the middle: this was 

 found in the infusion of hemp-seed, but is found in other vegetable infusions, particularly in that of 

 lea- seed. 



Fig. 2 is the volvox torquilla, or wryneck. At a is represented its divided state, at b and c its 

 natural shape; this is common to most vegetable infusions, as is the following. 



Fig. 3 is the volvox volutans, or the roller. At a the animal is separated, and becomes two dis- 

 tinct beings, each swimming about and providing for itself; this is often the prey of another species 

 of this genus, especially while it is weak by this separation, not being so active for some time till it 

 can recover itself. At c the animal appears to be hurt on one side; this impression, in a little time, 

 is succeeded by another on the opposite side, as at b, which soon occasions a division. At d is the 

 side view, and at e the front view of the natural shape of the animal. 



Fig. 4 is the volvox oniscus, or wood-louse. At a is the natural shape of it, as it appears full of 

 little hairs both at the head and tail ; with those at the head it whirls the water about, to draw its 

 prey to it; the feet, which are many, are very visible, but remarkably so in a side view at d. At 

 b it is represented beginning to divide, and at c the animals are ready to part : in this state, as if in 

 exquisite pain, they swim round and round, and to and fro, with uncommon velocity, violently agi- 

 tated till they get asunder. This was found in an infusion of different kinds of pine branches. 



Fig. 5 is the volvox leiebella, or the gimblet. This animal is one of the largest of the kind, and 

 is very visible to the naked eye. It moves along swiftly, turning itself round as it swims, just as if 

 boring its way; a and b are two views of its natural shape; c shows the manner of its dividing. 

 When they are separated, the lower animal rolls very aukwardly along till it gets a groove in the 

 upper part ; d represents one of them lyinj torpid, by means of the juice of the horseshoe geranium, 

 with its fins extended. This animal is found in many infusions, particularly of grass or corn. 



Fig. 6 is the volvox vorax, or the glutton. This animal was found in an infusion of the Tartarian 

 pine; it varies its shape very much, contracting and extending its proboscis, turning to and fro, in 

 various directions, as at a, b, c, d, e. It opens its proboscis underneath the extremity, when it 

 seizes its prey. The less active animals, that have lately been divided, such as those at fig. 2, a, and 

 fig, 3, a, serve it as food when they come in its way : these it swallows down instantly, as it is re- 

 presented at fig. 6, h and i. At f it is ready to divide, and at g it is divided, where the hinder part 

 of the divided animal has got a proboscis or beak, to procure nourishment for itself, and soon be- 

 comes a distinct being from the fore part. 



